Add an experimental basic_static_cstring template in example/

This introduces an alternative to basic_static_string designed for use
in POD types: Trivially copyable, having a sizeof == N + 1, with no
embedded NULs.

Placed in example/ to gather user feedback before committing to a public
API. See issue #23.

.appveyor.yml

@@ -107,10 +107,10 @@ environment:
       B2_CXXSTD: 11,14,1z
       B2_TOOLSET: gcc
 
-    - FLAVOR: mingw32
+    - FLAVOR: mingw64 (32-bit)
       APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2019
+      ADDPATH: C:\mingw-w64\i686-8.1.0-posix-dwarf-rt_v6-rev0\mingw32\bin;
       B2_ADDRESS_MODEL: 32
-      ADDPATH: C:\mingw\bin;
       B2_CXXSTD: 11,14,17,2a
       B2_TOOLSET: gcc
 

.drone.star

@@ -2,116 +2,116 @@
 # subject to the Boost Software License, Version 1.0. (See accompanying
 # file LICENSE.txt)
 #
-# Copyright Rene Rivera 2020.
-# Copyright Alan de Freitas 2022.
-
+# Copyright (c) 2020 Rene Rivera
+# Copyright (c) 2022 Alan de Freitas
+# Copyright (c) 2022-2025 Alexander Grund
 
 # For Drone CI we use the Starlark scripting language to reduce duplication.
 # As the yaml syntax for Drone CI is rather limited.
-#
-#
-globalenv={'B2_CI_VERSION': '1', 'B2_VARIANT': 'release'}
-linuxglobalimage="cppalliance/droneubuntu1804:1"
-windowsglobalimage="cppalliance/dronevs2019"
+
+# Base environment for all jobs
+globalenv={'B2_VARIANT': 'release'}
+
+# Wrapper function to apply the globalenv to all jobs
+def job(
+        # job specific environment options
+        env={},
+        **kwargs):
+  real_env = dict(globalenv)
+  real_env.update(env)
+  return job_impl(env=real_env, **kwargs)
 
 def main(ctx):
   return [
-  # Priorities: (no 2a, no betas)
-  #
-  # coverage
-  # latest gcc: 17,20
-  # latest clang: 17,20
-  # oldest gcc: 11
-  # oldest clang: 11
-  # asan
-  # tsan
-  # ubsan
-  # valgrind
-  # arm64
-  # s390x
-  # docs
-  # cmake superproject
-  # cmake install
-  # (...the rest)
+    job(compiler='clang-3.8', cxxstd='11,14',          os='ubuntu-16.04'),
+    job(compiler='clang-3.9', cxxstd='11,14',          os='ubuntu-18.04'),
+    job(compiler='clang-4.0', cxxstd='11,14',          os='ubuntu-18.04'),
+    job(compiler='clang-5.0', cxxstd='11,14,1z',       os='ubuntu-18.04'),
+    job(compiler='clang-6.0', cxxstd='11,14,17',       os='ubuntu-18.04'),
+    job(compiler='clang-7',   cxxstd='11,14,17',       os='ubuntu-18.04'),
+    job(compiler='clang-8',   cxxstd='11,14,17,2a',    os='ubuntu-18.04'),
+    job(compiler='clang-9',   cxxstd='11,14,17,2a',    os='ubuntu-18.04'),
+    job(compiler='clang-10',  cxxstd='11,14,17,2a',    os='ubuntu-18.04'),
+    job(compiler='clang-11',  cxxstd='11,14,17,2a',    os='ubuntu-22.04'),
+    job(compiler='clang-12',  cxxstd='11,14,17,20',    os='ubuntu-22.04'),
+    job(compiler='clang-13',  cxxstd='11,14,17,20,2b', os='ubuntu-22.04'),
+    job(compiler='clang-14',  cxxstd='11,14,17,20,2b', os='ubuntu-22.04'),
+    job(compiler='clang-15',  cxxstd='11,14,17,20,2b', os='ubuntu-22.04', add_llvm=True,
+        env={'B2_CXXFLAGS': '-Werror'}),
+    job(name='Clang 15 standalone', compiler='clang-15',  cxxstd='17,20,2b', os='ubuntu-22.04', add_llvm=True,
+        env={'B2_CXXFLAGS': '-Werror', 'B2_DEFINES': 'BOOST_STATIC_STRING_STANDALONE'}),
 
-  # Coverage
-  linux_cxx("Coverage", "g++-8", packages="g++-8", buildscript="drone", buildtype="codecov", image=linuxglobalimage, environment={'COMMENT': 'codecov.io', 'LCOV_BRANCH_COVERAGE': '0', 'B2_CXXSTD': '11', 'B2_TOOLSET': 'gcc-8', 'B2_DEFINES': 'BOOST_NO_STRESS_TEST=1', "CODECOV_TOKEN": {"from_secret": "codecov_token"}, "COVERALLS_REPO_TOKEN": {"from_secret": "coveralls_repo_token"}}, globalenv=globalenv),
+    job(compiler='gcc-4.8',   cxxstd='11',             os='ubuntu-16.04'),
+    job(compiler='gcc-4.9',   cxxstd='11',             os='ubuntu-16.04'),
+    job(compiler='gcc-5',     cxxstd='11,14,1z',       os='ubuntu-18.04'),
+    job(compiler='gcc-6',     cxxstd='11,14,1z',       os='ubuntu-18.04'),
+    job(compiler='gcc-7',     cxxstd='11,14,1z',       os='ubuntu-18.04'),
+    job(compiler='gcc-8',     cxxstd='11,14,17,2a',    os='ubuntu-18.04'),
+    job(compiler='gcc-9',     cxxstd='11,14,17,2a',    os='ubuntu-18.04'),
+    job(compiler='gcc-10',    cxxstd='11,14,17,20',    os='ubuntu-22.04'),
+    job(compiler='gcc-11',    cxxstd='11,14,17,20,2b', os='ubuntu-22.04'),
+    job(compiler='gcc-12',    cxxstd='11,14,17,20,2b', os='ubuntu-22.04'),
 
-  # Latest gcc
-  linux_cxx("GCC 12: C++17,20", "g++-12", packages="g++-12", buildscript="drone", buildtype="boost", image="cppalliance/droneubuntu2204:1", environment={'B2_TOOLSET': 'gcc-12', 'B2_CXXFLAGS': '-Werror', 'B2_CXXSTD': '17,20'}, globalenv=globalenv),
-  linux_cxx("GCC 12: C++17,20 Standalone", "g++-12", packages="g++-12", buildscript="drone", buildtype="boost", image="cppalliance/droneubuntu2204:1", environment={'B2_TOOLSET': 'gcc-12', 'B2_CXXFLAGS': '-Werror', 'B2_DEFINES': 'define=BOOST_STATIC_STRING_STANDALONE', 'B2_CXXSTD': '17,20'}, globalenv=globalenv),
+    job(name='Coverage', buildtype='codecov', buildscript='codecov_coveralls', env={'LCOV_BRANCH_COVERAGE': 1, "COVERALLS_REPO_TOKEN": {"from_secret": "coveralls_repo_token"}},
+        compiler='gcc-8',     cxxstd='11,14,17,2a',    os='ubuntu-18.04'),
+    # Sanitizers
+    job(name='ASAN',  asan=True,
+        compiler='gcc-12',    cxxstd='11,14,17,20',    os='ubuntu-22.04'),
+    job(name='UBSAN', ubsan=True,
+        compiler='gcc-12',    cxxstd='11,14,17,20',    os='ubuntu-22.04'),
+    job(name='TSAN',  tsan=True,
+        compiler='gcc-12',    cxxstd='11,14,17,20',    os='ubuntu-22.04'),
+    job(name='Clang 14 w/ sanitizers', asan=True, ubsan=True,
+        compiler='clang-14',  cxxstd='11,14,17,20',    os='ubuntu-22.04'),
+    job(name='Clang 11 libc++ w/ sanitizers', asan=True, ubsan=True, # libc++-11 is the latest working with ASAN: https://github.com/llvm/llvm-project/issues/59432
+        compiler='clang-11',  cxxstd='11,14,17,20',    os='ubuntu-20.04', stdlib='libc++', install='libc++-11-dev libc++abi-11-dev'),
+    job(name='Valgrind', valgrind=True,
+        compiler='clang-6.0', cxxstd='11,14,1z',       os='ubuntu-18.04', install='libc6-dbg libc++-dev libstdc++-8-dev'),
 
-  # Latest clang
-  linux_cxx("Clang 15: C++17,20", "clang++-15", packages="clang-15 libstdc++-10-dev", llvm_os="jammy", llvm_ver="15", buildscript="drone", buildtype="boost", image="cppalliance/droneubuntu2204:1", environment={'B2_TOOLSET': 'clang-15', 'B2_CXXFLAGS': '-Werror', 'B2_CXXSTD': '17,20'}, globalenv=globalenv),
-  linux_cxx("Clang 15: C++17,20 Standalone", "clang++-15", packages="clang-15 libstdc++-10-dev", llvm_os="jammy", llvm_ver="15", buildscript="drone", buildtype="boost", image="cppalliance/droneubuntu2204:1", environment={'B2_TOOLSET': 'clang-15', 'B2_CXXFLAGS': '-Werror', 'B2_DEFINES': 'define=BOOST_STATIC_STRING_STANDALONE', 'B2_CXXSTD': '17,20'}, globalenv=globalenv),
+    # libc++
+    job(compiler='clang-6.0', cxxstd='11,14,17,2a',    os='ubuntu-18.04', stdlib='libc++', install='libc++-dev libc++abi-dev'),
+    job(compiler='clang-7',   cxxstd='11,14,17,2a',    os='ubuntu-20.04', stdlib='libc++', install='libc++-7-dev libc++abi-7-dev'),
+    job(compiler='clang-8',   cxxstd='11,14,17,2a',    os='ubuntu-20.04', stdlib='libc++', install='libc++-8-dev libc++abi-8-dev'),
+    job(compiler='clang-9',   cxxstd='11,14,17,2a',    os='ubuntu-20.04', stdlib='libc++', install='libc++-9-dev libc++abi-9-dev'),
+    job(compiler='clang-10',  cxxstd='11,14,17,20',    os='ubuntu-20.04', stdlib='libc++', install='libc++-10-dev libc++abi-10-dev'),
+    job(compiler='clang-11',  cxxstd='11,14,17,20',    os='ubuntu-20.04', stdlib='libc++', install='libc++-11-dev libc++abi-11-dev'),
+    job(compiler='clang-12',  cxxstd='11,14,17,20',    os='ubuntu-22.04', stdlib='libc++', install='libc++-12-dev libc++abi-12-dev libunwind-12-dev'),
+    job(compiler='clang-13',  cxxstd='11,14,17,20',    os='ubuntu-22.04', stdlib='libc++', install='libc++-13-dev libc++abi-13-dev'),
+    job(compiler='clang-14',  cxxstd='11,14,17,20',    os='ubuntu-22.04', stdlib='libc++', install='libc++-14-dev libc++abi-14-dev'),
+    job(compiler='clang-15',  cxxstd='11,14,17,20',    os='ubuntu-22.04', stdlib='libc++', install='libc++-15-dev libc++abi-15-dev', add_llvm=True),
 
-  # Oldest compilers
-  linux_cxx("GCC 4.8: C++11", "g++-4.8", packages="g++-4.8", buildscript="drone", buildtype="boost", image="cppalliance/droneubuntu1604:1", environment={'B2_TOOLSET': 'gcc-4.8', 'B2_CXXFLAGS': '-Werror', 'B2_CXXSTD': '11'}, globalenv=globalenv),
-  linux_cxx("GCC 4.8: C++11 Standalone", "g++-4.8", packages="g++-4.8", buildscript="drone", buildtype="boost", image="cppalliance/droneubuntu1604:1", environment={'B2_TOOLSET': 'gcc-4.8', 'B2_CXXFLAGS': '-Werror', 'B2_DEFINES': 'define=BOOST_STATIC_STRING_STANDALONE', 'B2_CXXSTD': '11'}, globalenv=globalenv),
-  linux_cxx("Clang 3.8: C++11", "clang++-3.8", packages="clang-3.8", buildscript="drone", buildtype="boost", image="cppalliance/droneubuntu1604:1", environment={'B2_VARIANT': 'debug', 'B2_CXXFLAGS': '-Werror', 'B2_TOOLSET': 'clang-3.8', 'B2_CXXSTD': '11'}, globalenv=globalenv),
-  linux_cxx("Clang 3.8: C++11 Standalone", "clang++-3.8", packages="clang-3.8", buildscript="drone", buildtype="boost", image="cppalliance/droneubuntu1604:1", environment={'B2_VARIANT': 'debug', 'B2_CXXFLAGS': '-Werror', 'B2_TOOLSET': 'clang-3.8', 'B2_DEFINES': 'define=BOOST_STATIC_STRING_STANDALONE', 'B2_CXXSTD': '11'}, globalenv=globalenv),
-
-  # Sanitizers + Valgrind
-  linux_cxx("ASan", "g++-12", packages="g++-12", buildscript="drone", buildtype="boost", image="cppalliance/droneubuntu2204:1", environment={'COMMENT': 'asan', 'B2_VARIANT': 'debug', 'B2_TOOLSET': 'gcc-12', 'B2_CXXSTD': '11,14,17', 'B2_ASAN': '1', 'B2_DEFINES': 'BOOST_NO_STRESS_TEST=1', 'DRONE_EXTRA_PRIVILEGED': 'True'}, globalenv=globalenv, privileged=True),
-  linux_cxx("TSan", "g++-12", packages="g++-12", buildscript="drone", buildtype="boost", image="cppalliance/droneubuntu2204:1", environment={'COMMENT': 'tsan', 'B2_VARIANT': 'debug', 'B2_TOOLSET': 'gcc-12', 'B2_CXXSTD': '11,14,17', 'B2_TSAN': '1', 'B2_DEFINES': 'BOOST_NO_STRESS_TEST=1'}, globalenv=globalenv),
-  linux_cxx("UBSan", "g++-12", packages="g++-12", buildscript="drone", buildtype="boost", image="cppalliance/droneubuntu2204:1", environment={'COMMENT': 'ubsan', 'B2_VARIANT': 'debug', 'B2_TOOLSET': 'gcc-12', 'B2_CXXSTD': '11,14,17', 'B2_UBSAN': '1', 'B2_DEFINES': 'define=BOOST_NO_STRESS_TEST=1', 'B2_LINKFLAGS': '-fuse-ld=gold'}, globalenv=globalenv),
-  linux_cxx("Valgrind", "clang++-14", packages="clang-14 libc6-dbg libc++-dev libstdc++-9-dev", llvm_os="jammy", llvm_ver="14", buildscript="drone", buildtype="valgrind", image="cppalliance/droneubuntu2204:1", environment={'COMMENT': 'valgrind', 'B2_TOOLSET': 'clang-14', 'B2_CXXSTD': '11,14,17', 'B2_DEFINES': 'BOOST_NO_STRESS_TEST=1', 'B2_VARIANT': 'debug', 'B2_TESTFLAGS': 'testing.launcher=valgrind', 'VALGRIND_OPTS': '--error-exitcode=1'}, globalenv=globalenv),
-
-  # arm64 (unsigned char)
-  linux_cxx("ARM64: GCC 11", "g++-11", packages="g++-11", buildscript="drone", buildtype="boost", image="cppalliance/droneubuntu2004:multiarch", environment={'B2_TOOLSET': 'gcc-11', 'B2_CXXFLAGS': '-Werror', 'B2_CXXSTD': '17,20'}, arch="arm64", globalenv=globalenv),
-
-  # s390x
-  linux_cxx("S390x: Clang 12", "clang++-12", packages="clang-12 libstdc++-9-dev", llvm_os="focal", llvm_ver="12", buildtype="boost", buildscript="drone", image="cppalliance/droneubuntu2004:multiarch", environment={'B2_TOOLSET': 'clang-12', 'B2_CXXFLAGS': '-Werror', 'B2_CXXSTD': '17,20'}, arch="s390x", globalenv=globalenv),
-
-  # Documentation
-  # linux_cxx("Docs", "g++", packages="docbook docbook-xml docbook-xsl xsltproc libsaxonhe-java default-jre-headless flex libfl-dev bison unzip rsync", buildtype="docs", buildscript="drone", image="cppalliance/droneubuntu1804:1", environment={'COMMENT': 'docs'}, globalenv=globalenv),
-
-  # CMake tests (https://github.com/boostorg/boost-ci)
-  ## Compiling as part of the boost superproject
-  linux_cxx("CMake Superproject", "g++", packages="", buildscript="drone", buildtype="cmake-superproject", image="cppalliance/droneubuntu1804:1", globalenv=globalenv),
-  ## Installing
-  # linux_cxx("CMake Install", "g++", packages="", buildscript="drone", buildtype="cmake1", image="cppalliance/droneubuntu1804:1", environment={'CMAKE_INSTALL_TEST': '1'}, globalenv=globalenv),
-
-  # ------------------------------------------------------------------
-
-  # OSX
-  osx_cxx("OSX: Clang", "g++", packages="", buildscript="drone", buildtype="boost", xcode_version="13.4.1", environment={'B2_TOOLSET': 'clang', 'B2_CXXFLAGS': '-Werror', 'B2_CXXSTD': '11,17'}, globalenv=globalenv),
-
-  # GCC (All other versions)
-  linux_cxx("GCC 4.9: C++11", "g++-4.9", packages="g++-4.9", buildscript="drone", buildtype="boost", image="cppalliance/droneubuntu1604:1", environment={'B2_TOOLSET': 'gcc-4.9', 'B2_CXXFLAGS': '-Werror', 'B2_CXXSTD': '11'}, globalenv=globalenv),
-  linux_cxx("GCC 5: C++11", "g++-5", packages="g++-5", buildscript="drone", buildtype="boost", image=linuxglobalimage, environment={'B2_TOOLSET': 'gcc-5', 'B2_CXXFLAGS': '-Werror', 'B2_CXXSTD': '11'}, globalenv=globalenv),
-  linux_cxx("GCC 6: C++11,14", "g++-6", packages="g++-6", buildscript="drone", buildtype="boost", image=linuxglobalimage, environment={'B2_TOOLSET': 'gcc-6', 'B2_CXXFLAGS': '-Werror', 'B2_CXXSTD': '11,14'}, globalenv=globalenv),
-  linux_cxx("GCC 7: C++14,17", "g++-7", packages="g++-7", buildscript="drone", buildtype="boost", image=linuxglobalimage, environment={'B2_TOOLSET': 'gcc-7', 'B2_CXXFLAGS': '-Werror', 'B2_CXXSTD': '14,17'}, globalenv=globalenv),
-  linux_cxx("GCC 8: C++17", "g++-8", packages="g++-8", buildscript="drone", buildtype="boost", image=linuxglobalimage, environment={'B2_TOOLSET': 'gcc-8', 'B2_CXXFLAGS': '-Werror', 'B2_CXXSTD': '17'}, globalenv=globalenv),
-  linux_cxx("GCC 9: C++17", "g++-9", packages="g++-9", buildscript="drone", buildtype="boost", image=linuxglobalimage, environment={'B2_TOOLSET': 'gcc-9', 'B2_CXXFLAGS': '-Werror', 'B2_CXXSTD': '17'}, globalenv=globalenv),
-  linux_cxx("GCC 10: C++17", "g++-10", packages="g++-10", buildscript="drone", buildtype="boost", image=linuxglobalimage, environment={'B2_TOOLSET': 'gcc-10', 'B2_CXXFLAGS': '-Werror', 'B2_CXXSTD': '17'}, globalenv=globalenv),
-  linux_cxx("GCC 11: C++17,20", "g++-11", packages="g++-11", buildscript="drone", buildtype="boost", image=linuxglobalimage, environment={'B2_TOOLSET': 'gcc-11', 'B2_CXXFLAGS': '-Werror', 'B2_CXXSTD': '17,20'}, globalenv=globalenv),
-
-  # Clang (All other versions)
-  linux_cxx("Clang 4.0: C++11,14", "clang++-4.0", packages="clang-4.0 libstdc++-6-dev", llvm_os="xenial", llvm_ver="4.0", buildscript="drone", buildtype="boost", image="cppalliance/droneubuntu1804:1", environment={'B2_TOOLSET': 'clang-4.0', 'B2_CXXFLAGS': '', 'B2_CXXSTD': '11,14'}, globalenv=globalenv),
-  linux_cxx("Clang 5.0: C++11,14", "clang++-5.0", packages="clang-5.0 libstdc++-7-dev", llvm_os="bionic", llvm_ver="5.0", buildscript="drone", buildtype="boost", image=linuxglobalimage, environment={'B2_TOOLSET': 'clang-5.0', 'B2_CXXFLAGS': '', 'B2_CXXSTD': '11,14'}, globalenv=globalenv),
-  linux_cxx("Clang 6.0: C++11,14", "clang++-6.0", packages="clang-6.0 libc6-dbg libc++-dev libc++abi-dev libstdc++-8-dev", llvm_os="bionic", llvm_ver="6.0", buildscript="drone", buildtype="boost", image=linuxglobalimage, environment={'B2_TOOLSET': 'clang-6.0', 'B2_CXXFLAGS': '-Werror', 'B2_CXXSTD': '11,14', 'B2_STDLIB': 'libc++'}, globalenv=globalenv),
-  linux_cxx("Clang 6.0: C++14,17", "clang++-6.0", packages="clang-6.0 libc6-dbg libc++-dev libc++abi-dev libstdc++-8-dev", llvm_os="bionic", llvm_ver="6.0", buildscript="drone", buildtype="boost", image=linuxglobalimage, environment={'B2_TOOLSET': 'clang-6.0', 'B2_CXXFLAGS': '-Werror', 'B2_CXXSTD': '14,17'}, globalenv=globalenv),
-  linux_cxx("Clang 7: C++17", "clang++-7", packages="clang-7 libc6-dbg libc++-dev libstdc++-8-dev", llvm_os="bionic", llvm_ver="7", buildscript="drone", buildtype="boost", image=linuxglobalimage, environment={'B2_TOOLSET': 'clang-7', 'B2_CXXFLAGS': '-Werror', 'B2_CXXSTD': '17'}, globalenv=globalenv),
-  linux_cxx("Clang 8: C++17", "clang++-8", packages="clang-8 libc6-dbg libc++-dev libstdc++-8-dev", llvm_os="bionic", llvm_ver="8", buildscript="drone", buildtype="boost", image=linuxglobalimage, environment={'B2_TOOLSET': 'clang-8', 'B2_CXXFLAGS': '-Werror', 'B2_CXXSTD': '17'}, globalenv=globalenv),
-  linux_cxx("Clang 9: C++14,17", "clang++-9", packages="clang-9 libstdc++-9-dev", llvm_os="bionic", llvm_ver="9", buildscript="drone", buildtype="boost", image=linuxglobalimage, environment={'B2_TOOLSET': 'clang-9', 'B2_CXXFLAGS': '-Werror', 'B2_CXXSTD': '14,17'}, globalenv=globalenv),
-  linux_cxx("Clang 10: C++14,17", "clang++-10", packages="clang-10 libstdc++-9-dev", llvm_os="focal", llvm_ver="10", buildscript="drone", buildtype="boost", image="cppalliance/droneubuntu2004:1", environment={'B2_TOOLSET': 'clang-10', 'B2_CXXFLAGS': '-Werror', 'B2_CXXSTD': '14,17'}, globalenv=globalenv),
-  linux_cxx("Clang 11: C++14,17", "clang++-11", packages="clang-11 libstdc++-9-dev", llvm_os="focal", llvm_ver="11", buildscript="drone", buildtype="boost", image="cppalliance/droneubuntu2004:1", environment={'B2_TOOLSET': 'clang-11', 'B2_CXXFLAGS': '-Werror', 'B2_CXXSTD': '14,17'}, globalenv=globalenv),
-  linux_cxx("Clang 12: C++17,20", "clang++-12", packages="clang-12 libstdc++-9-dev", llvm_os="focal", llvm_ver="12", buildscript="drone", buildtype="boost", image="cppalliance/droneubuntu2004:1", environment={'B2_TOOLSET': 'clang-12', 'B2_CXXFLAGS': '-Werror', 'B2_CXXSTD': '17,20'}, globalenv=globalenv),
-  linux_cxx("Clang 13: C++17,20", "clang++-13", packages="clang-13 libstdc++-10-dev", llvm_os="jammy", llvm_ver="13", buildscript="drone", buildtype="boost", image="cppalliance/droneubuntu2204:1", environment={'B2_TOOLSET': 'clang-13', 'B2_CXXFLAGS': '-Werror', 'B2_CXXSTD': '17,20'}, globalenv=globalenv),
-  linux_cxx("Clang 14: C++17,20", "clang++-14", packages="clang-14 libstdc++-10-dev", llvm_os="jammy", llvm_ver="14", buildscript="drone", buildtype="boost", image="cppalliance/droneubuntu2204:1", environment={'B2_TOOLSET': 'clang-14', 'B2_CXXFLAGS': '-Werror', 'B2_CXXSTD': '17,20'}, globalenv=globalenv),
-
-  # arm64 (unsigned char)
-  linux_cxx("ARM64: Clang 12", "clang++-12", packages="clang-12 libstdc++-9-dev", llvm_os="focal", llvm_ver="12", buildscript="drone", buildtype="boost", image="cppalliance/droneubuntu2004:multiarch", environment={'B2_TOOLSET': 'clang-12', 'B2_CXXFLAGS': '-Werror', 'B2_CXXSTD': '11,14,17,20'}, arch="arm64", globalenv=globalenv),
-
-  # s390x
-  linux_cxx("S390x: GCC 11", "g++-11", packages="g++-11", buildtype="boost", buildscript="drone", image="cppalliance/droneubuntu2004:multiarch", environment={'B2_TOOLSET': 'gcc-11', 'B2_CXXFLAGS': '-Werror', 'B2_CXXSTD': '17'}, arch="s390x", globalenv=globalenv),
-
-  # MSVC
-  windows_cxx("MSVC 14.1", "", image="cppalliance/dronevs2017", buildtype="boost", buildscript="drone", environment={"B2_TOOLSET": "msvc-14.1", 'B2_CXXFLAGS': '/WX', "B2_CXXSTD": "11,14,17"},globalenv=globalenv),
-  windows_cxx("MSVC 14.2: C++14,17,latest", "", image="cppalliance/dronevs2019", buildtype="boost", buildscript="drone", environment={"B2_TOOLSET": "msvc-14.2", 'B2_CXXFLAGS': '/WX', "B2_CXXSTD": "14,17,latest"},globalenv=globalenv),
-  windows_cxx("MSVC 14.3: C++17,20", "", image="cppalliance/dronevs2022", buildtype="boost", buildscript="drone", environment={"B2_TOOLSET": "msvc-14.3", 'B2_CXXFLAGS': '/WX', "B2_CXXSTD": "17,20"},globalenv=globalenv),
-]
+    # FreeBSD
+    job(compiler='clang-10',  cxxstd='11,14,17,20',    os='freebsd-13.1'),
+    job(compiler='clang-15',  cxxstd='11,14,17,20',    os='freebsd-13.1'),
+    job(compiler='gcc-11',    cxxstd='11,14,17,20',    os='freebsd-13.1', linkflags='-Wl,-rpath=/usr/local/lib/gcc11'),
+    # OSX
+    job(compiler='clang',     cxxstd='11,14,17,2a',    os='osx-xcode-10.1'),
+    job(compiler='clang',     cxxstd='11,14,17,2a',    os='osx-xcode-10.3'),
+    job(compiler='clang',     cxxstd='11,14,17,2a',    os='osx-xcode-11.1'),
+    job(compiler='clang',     cxxstd='11,14,17,2a',    os='osx-xcode-11.7'),
+    job(compiler='clang',     cxxstd='11,14,17,2a',    os='osx-xcode-12'),
+    job(compiler='clang',     cxxstd='11,14,17,20',    os='osx-xcode-12.5.1'),
+    job(compiler='clang',     cxxstd='11,14,17,20',    os='osx-xcode-13.0'),
+    job(compiler='clang',     cxxstd='11,14,17,20',    os='osx-xcode-13.4.1'),
+    job(compiler='clang',     cxxstd='11,14,17,20,2b', os='osx-xcode-14.0'),
+    job(compiler='clang',     cxxstd='11,14,17,20,2b', os='osx-xcode-14.3.1'),
+    job(compiler='clang',     cxxstd='11,14,17,20,2b', os='osx-xcode-15.0.1'),
+    # ARM64
+    job(compiler='clang-12',  cxxstd='11,14,17,20',    os='ubuntu-20.04', arch='arm64', add_llvm=True),
+    job(compiler='gcc-11',    cxxstd='11,14,17,20',    os='ubuntu-20.04', arch='arm64'),
+    # S390x
+    job(compiler='clang-12',  cxxstd='11,14,17,20',    os='ubuntu-20.04', arch='s390x', add_llvm=True),
+    job(compiler='gcc-11',    cxxstd='11,14,17,20',    os='ubuntu-20.04', arch='s390x'),
+    # Windows
+    job(compiler='msvc-14.0', cxxstd=None,              os='windows', env={'B2_DONT_EMBED_MANIFEST': 1}),
+    job(compiler='msvc-14.1', cxxstd=None,              os='windows'),
+    job(compiler='msvc-14.2', cxxstd=None,              os='windows'),
+    job(compiler='msvc-14.3', cxxstd=None,              os='windows'),
+    job(compiler='msvc-14.0', cxxstd='14,17,20',        os='windows', env={'B2_DONT_EMBED_MANIFEST': 1}),
+    job(compiler='msvc-14.1', cxxstd='14,17,20',        os='windows'),
+    job(compiler='msvc-14.2', cxxstd='14,17,20',        os='windows'),
+    job(compiler='msvc-14.3', cxxstd='14,17,20,latest', os='windows'),
+  ]
 
 # from https://github.com/boostorg/boost-ci
-load("@boost_ci//ci/drone/:functions.star", "linux_cxx","windows_cxx","osx_cxx","freebsd_cxx")
+load("@boost_ci//ci/drone/:functions.star", "linux_cxx", "windows_cxx", "osx_cxx", "freebsd_cxx", "job_impl")

.drone/codecov_coveralls.sh

@@ -0,0 +1,28 @@
+#!/bin/bash
+
+# Copyright 2020 Rene Rivera, Sam Darwin
+# Copyright 2025 Alexander Grund
+# Distributed under the Boost Software License, Version 1.0.
+# (See accompanying file LICENSE.txt or copy at http://boost.org/LICENSE_1_0.txt)
+
+
+set -xe
+
+# Run the regular Boost CI script which does the test & upload to codecov.io
+wget https://github.com/boostorg/boost-ci/raw/refs/heads/master/.drone/drone.sh
+. drone.sh
+
+# coveralls
+# uses multiple lcov steps from boost-ci codecov.sh script
+if [ -n "${COVERALLS_REPO_TOKEN}" ]; then
+    echo "processing coveralls"
+    pip3 install --user cpp-coveralls
+    cd "$BOOST_CI_SRC_FOLDER"
+
+    export PATH=/tmp/lcov/bin:$PATH
+    command -v lcov
+    lcov --version
+
+    lcov --remove coverage.info -o coverage_filtered.info '*/test/*' '*/extra/*'
+    cpp-coveralls --verbose -l coverage_filtered.info
+fi

.drone/drone.bat

@@ -1,31 +0,0 @@
-
-@ECHO ON
-setlocal enabledelayedexpansion
-
-if "%DRONE_JOB_BUILDTYPE%" == "boost" (
-
-echo '==================================> INSTALL'
-
-git clone https://github.com/boostorg/boost-ci.git boost-ci-cloned --depth 1
-cp -prf boost-ci-cloned/ci .
-rm -rf boost-ci-cloned
-REM source ci/travis/install.sh
-REM The contents of install.sh below:
-
-for /F %%i in ("%DRONE_REPO%") do @set SELF=%%~nxi
-SET BOOST_CI_TARGET_BRANCH=%DRONE_COMMIT_BRANCH%
-SET BOOST_CI_SRC_FOLDER=%cd%
-
-call ci\common_install.bat
-
-echo '==================================> COMPILE'
-
-REM set B2_TARGETS=libs/!SELF!/test libs/!SELF!/example
-set B2_TARGETS=libs/!SELF!/test
-call !BOOST_ROOT!\libs\!SELF!\ci\build.bat
-
-) else if "%DRONE_JOB_BUILDTYPE%" == "standalone-windows" (
-
-REM not used
-
-)

.drone/drone.sh

@@ -1,236 +0,0 @@
-#!/bin/bash
-
-# Copyright 2020 Rene Rivera, Sam Darwin
-# Distributed under the Boost Software License, Version 1.0.
-# (See accompanying file LICENSE.txt or copy at http://boost.org/LICENSE_1_0.txt)
-
-set -xe
-
-export TRAVIS_BUILD_DIR=$(pwd)
-export DRONE_BUILD_DIR=$(pwd)
-export TRAVIS_BRANCH=$DRONE_BRANCH
-export TRAVIS_EVENT_TYPE=$DRONE_BUILD_EVENT
-export VCS_COMMIT_ID=$DRONE_COMMIT
-export GIT_COMMIT=$DRONE_COMMIT
-export REPO_NAME=$DRONE_REPO
-export USER=$(whoami)
-export CC=${CC:-gcc}
-export PATH=~/.local/bin:/usr/local/bin:$PATH
-
-common_install() {
-  git clone https://github.com/boostorg/boost-ci.git boost-ci-cloned --depth 1
-  cp -prf boost-ci-cloned/ci .
-  rm -rf boost-ci-cloned
-
-  if [ "$TRAVIS_OS_NAME" == "osx" ]; then
-    unset -f cd
-  fi
-
-  export SELF=$(basename $REPO_NAME)
-  export BOOST_CI_TARGET_BRANCH="$TRAVIS_BRANCH"
-  export BOOST_CI_SRC_FOLDER=$(pwd)
-
-  . ./ci/common_install.sh
-}
-
-if [ "$DRONE_JOB_BUILDTYPE" == "boost" ]; then
-
-  echo '==================================> INSTALL'
-
-  common_install
-
-  echo '==================================> SCRIPT'
-
-  export B2_TARGETS=${B2_TARGETS:-"libs/$SELF/test"}
-  $BOOST_ROOT/libs/$SELF/ci/travis/build.sh
-
-elif [ "$DRONE_JOB_BUILDTYPE" == "docs" ]; then
-
-  echo '==================================> INSTALL'
-
-  export SELF=$(basename $REPO_NAME)
-
-  pwd
-  cd ..
-  mkdir -p $HOME/cache && cd $HOME/cache
-  if [ ! -d doxygen ]; then git clone -b 'Release_1_8_15' --depth 1 https://github.com/doxygen/doxygen.git && echo "not-cached"; else echo "cached"; fi
-  cd doxygen
-  cmake -H. -Bbuild -DCMAKE_BUILD_TYPE=Release
-  cd build
-  sudo make install
-  cd ../..
-  if [ ! -f saxonhe.zip ]; then wget -O saxonhe.zip https://sourceforge.net/projects/saxon/files/Saxon-HE/9.9/SaxonHE9-9-1-4J.zip/download && echo "not-cached"; else echo "cached"; fi
-  unzip -o saxonhe.zip
-  sudo rm /usr/share/java/Saxon-HE.jar
-  sudo cp saxon9he.jar /usr/share/java/Saxon-HE.jar
-  cd ..
-  BOOST_BRANCH=develop && [ "$TRAVIS_BRANCH" == "master" ] && BOOST_BRANCH=master || true
-  git clone -b $BOOST_BRANCH https://github.com/boostorg/boost.git boost-root --depth 1
-  cd boost-root
-  export BOOST_ROOT=$(pwd)
-  git submodule update --init libs/context
-  git submodule update --init tools/boostbook
-  git submodule update --init tools/boostdep
-  git submodule update --init tools/docca
-  git submodule update --init tools/quickbook
-  rsync -av $TRAVIS_BUILD_DIR/ libs/$SELF
-  python tools/boostdep/depinst/depinst.py ../tools/quickbook
-  ./bootstrap.sh
-  ./b2 headers
-
-  echo '==================================> SCRIPT'
-
-  echo "using doxygen ; using boostbook ; using saxonhe ;" >tools/build/src/user-config.jam
-  ./b2 -j3 libs/$SELF/doc//boostrelease
-
-elif [ "$DRONE_JOB_BUILDTYPE" == "codecov" ]; then
-
-  echo '==================================> INSTALL'
-
-  common_install
-
-  echo '==================================> SCRIPT'
-
-  set +e
-
-  cd $BOOST_ROOT/libs/$SELF
-  ci/travis/codecov.sh
-
-  # coveralls
-  # uses multiple lcov steps from boost-ci codecov.sh script
-  if [ -n "${COVERALLS_REPO_TOKEN}" ]; then
-    echo "processing coveralls"
-    pip3 install --user cpp-coveralls
-    cd $BOOST_CI_SRC_FOLDER
-
-    export PATH=/tmp/lcov/bin:$PATH
-    command -v lcov
-    lcov --version
-
-    lcov --remove coverage.info -o coverage_filtered.info '*/test/*' '*/extra/*'
-    cpp-coveralls --verbose -l coverage_filtered.info
-  fi
-
-elif [ "$DRONE_JOB_BUILDTYPE" == "valgrind" ]; then
-
-  echo '==================================> INSTALL'
-
-  common_install
-
-  echo '==================================> SCRIPT'
-
-  cd $BOOST_ROOT/libs/$SELF
-  ci/travis/valgrind.sh
-
-elif [ "$DRONE_JOB_BUILDTYPE" == "standalone" ]; then
-
-  echo '==================================> INSTALL'
-
-  # Installing cmake with apt-get, so not required here:
-  # pip install --user cmake
-
-  echo '==================================> SCRIPT'
-
-  export CXXFLAGS="-Wall -Wextra -Werror -std=c++17"
-  mkdir __build_17
-  cd __build_17
-  cmake -DBOOST_JSON_STANDALONE=1 ..
-  cmake --build .
-  ctest -V .
-  export CXXFLAGS="-Wall -Wextra -Werror -std=c++2a"
-  mkdir ../__build_2a
-  cd ../__build_2a
-  cmake -DBOOST_JSON_STANDALONE=1 ..
-  cmake --build .
-  ctest -V .
-
-elif [ "$DRONE_JOB_BUILDTYPE" == "coverity" ]; then
-
-  echo '==================================> INSTALL'
-
-  common_install
-
-  echo '==================================> SCRIPT'
-
-  if [ -n "${COVERITY_SCAN_NOTIFICATION_EMAIL}" -a \( "$TRAVIS_BRANCH" = "develop" -o "$TRAVIS_BRANCH" = "master" \) -a \( "$DRONE_BUILD_EVENT" = "push" -o "$DRONE_BUILD_EVENT" = "cron" \) ]; then
-    cd $BOOST_ROOT/libs/$SELF
-    ci/travis/coverity.sh
-  fi
-
-elif [ "$DRONE_JOB_BUILDTYPE" == "cmake-superproject" ]; then
-
-  echo '==================================> INSTALL'
-
-  common_install
-
-  echo '==================================> COMPILE'
-
-  # May want to re-enable -Werror
-  # export CXXFLAGS="-Wall -Wextra -Werror"
-  export CXXFLAGS="-Wall -Wextra"
-
-  mkdir __build_static
-  cd __build_static
-  cmake -DBOOST_ENABLE_CMAKE=1 -DBUILD_TESTING=ON -DBoost_VERBOSE=1 \
-    -DBOOST_INCLUDE_LIBRARIES=$SELF ..
-  cmake --build .
-  ctest --output-on-failure -R boost_$SELF
-
-  cd ..
-
-  mkdir __build_shared
-  cd __build_shared
-  cmake -DBOOST_ENABLE_CMAKE=1 -DBUILD_TESTING=ON -DBoost_VERBOSE=1 \
-    -DBOOST_INCLUDE_LIBRARIES=$SELF -DBUILD_SHARED_LIBS=ON ..
-  cmake --build .
-  ctest --output-on-failure -R boost_$SELF
-
-elif [ "$DRONE_JOB_BUILDTYPE" == "cmake1" ]; then
-
-  echo '==================================> INSTALL'
-
-  # https://github.com/opencv/opencv-python#frequently-asked-questions
-  pip install --upgrade pip
-  pip install --user cmake
-
-  echo '==================================> SCRIPT'
-
-  export SELF=$(basename $REPO_NAME)
-  BOOST_BRANCH=develop && [ "$DRONE_BRANCH" == "master" ] && BOOST_BRANCH=master || true
-  echo BOOST_BRANCH: $BOOST_BRANCH
-  cd ..
-  git clone -b $BOOST_BRANCH --depth 1 https://github.com/boostorg/boost.git boost-root
-  cd boost-root
-  # mkdir -p libs/$SELF
-  # cp -r $DRONE_BUILD_DIR/* libs/$SELF
-  # git submodule update --init tools/boostdep
-  git submodule update --init --recursive
-  mkdir -p libs/$SELF
-  cp -r $DRONE_BUILD_DIR/* libs/$SELF
-
-  # CMake tests
-  cd libs/$SELF
-  mkdir __build__ && cd __build__
-  cmake -DCMAKE_INSTALL_PREFIX=~/.local ..
-  cmake --build . --target install
-  ctest --output-on-failure
-
-  # CMake subdir tests
-  cd ../test/cmake_test && mkdir __build__ && cd __build__
-  cmake -DCMAKE_INSTALL_PREFIX=~/.local ..
-  cmake --build .
-  cmake --build . --target check
-  ctest --output-on-failure
-
-  # Install Library
-  cd ../../../../.. && mkdir __build_cmake_install_test__ && cd __build_cmake_install_test__
-  cmake -DBOOST_INCLUDE_LIBRARIES=$SELF -DCMAKE_INSTALL_PREFIX=~/.local -DBoost_VERBOSE=ON -DBoost_DEBUG=ON ..
-  cmake --build . --target install
-
-  # CMake install tests
-  cd ../libs/$SELF/test/cmake_test && mkdir __build_cmake_install_test__ && cd __build_cmake_install_test__
-  cmake -DBOOST_CI_INSTALL_TEST=ON -DCMAKE_PREFIX_PATH=~/.local ..
-  cmake --build .
-  ctest --output-on-failure
-
-fi

.github/workflows/ci.yml

@@ -1,10 +1,19 @@
+#
 # Copyright 2020-2021 Peter Dimov
 # Copyright 2021 Andrey Semashev
-# Copyright 2022 Alan de Freitas
+# Copyright 2021-2025 Alexander Grund
+# Copyright 2022-2025 James E. King III
 #
 # Distributed under the Boost Software License, Version 1.0.
 # (See accompanying file LICENSE_1_0.txt or copy at http://boost.org/LICENSE_1_0.txt)
-
+#
+# This workflow uses the Boost.CI reusable workflow which builds a variety of
+# configurations of your project, runs tests, and generates code coverage reports.
+#
+# To use it, copy this file into your repository as `.github/workflows/ci.yml` and
+# customize it appropriately.
+# 
+---
 name: CI
 
 on:
@@ -13,510 +22,29 @@ on:
     branches:
       - master
       - develop
+      - bugfix/**
       - feature/**
-
-concurrency:
-  group: ${{format('{0}:{1}', github.repository, github.ref)}}
-  cancel-in-progress: true
-
-env:
-  GIT_FETCH_JOBS: 8
-  NET_RETRY_COUNT: 5
-  DEFAULT_BUILD_VARIANT: debug,release
+      - fix/**
+      - github/**
+      - pr/**
+    paths-ignore:
+      - LICENSE
+      - meta/**
+      - README.md
 
 jobs:
-  posix:
-    defaults:
-      run:
-        shell: bash
-
-    strategy:
-      fail-fast: false
-      matrix:
-        include:
-          # Linux, gcc
-          - toolset: gcc-4.8
-            cxxstd: "11"
-            os: ubuntu-22.04
-            container: ubuntu:18.04
-            install:
-              - g++-4.8
-          - toolset: gcc-4.9
-            cxxstd: "11"
-            os: ubuntu-22.04
-            container: ubuntu:16.04
-            install:
-              - g++-4.9
-          - toolset: gcc-5
-            cxxstd: "11,14"
-            os: ubuntu-22.04
-            container: ubuntu:16.04
-            install:
-              - g++-5
-          - toolset: gcc-6
-            cxxstd: "11,14"
-            os: ubuntu-22.04
-            container: ubuntu:18.04
-            install:
-              - g++-6
-          - toolset: gcc-7
-            cxxstd: "14,17"
-            os: ubuntu-22.04
-            container: ubuntu:18.04
-            install:
-              - g++-7
-          - toolset: gcc-8
-            cxxstd: "17"
-            os: ubuntu-22.04
-            container: ubuntu:18.04
-            install:
-              - g++-8
-          - toolset: gcc-9
-            cxxstd: "17"
-            os: ubuntu-22.04
-            install:
-              - g++-9
-          - toolset: gcc-10
-            cxxstd: "17"
-            os: ubuntu-22.04
-            install:
-              - g++-10
-          - toolset: gcc-11
-            cxxstd: "17,20"
-            os: ubuntu-22.04
-            install:
-              - g++-11
-            sources:
-              - "ppa:ubuntu-toolchain-r/test"
-          - name: UBSAN
-            toolset: gcc-11
-            cxxstd: "17,20"
-            ubsan: 1
-            os: ubuntu-22.04
-            install:
-              - g++-11
-            sources:
-              - "ppa:ubuntu-toolchain-r/test"
-
-          # Linux, clang
-          - toolset: clang
-            compiler: clang++-3.8
-            cxxstd: "11"
-            os: ubuntu-22.04
-            container: ubuntu:16.04
-            install:
-              - clang-3.8
-          - toolset: clang
-            compiler: clang++-4.0
-            cxxstd: "11,14"
-            os: ubuntu-22.04
-            container: ubuntu:18.04
-            install:
-              - clang-4.0
-          - toolset: clang
-            compiler: clang++-5.0
-            cxxstd: "11,14"
-            os: ubuntu-22.04
-            container: ubuntu:18.04
-            install:
-              - clang-5.0
-          - toolset: clang
-            compiler: clang++-6.0
-            cxxstd: "14,17"
-            os: ubuntu-22.04
-            container: ubuntu:18.04
-            install:
-              - clang-6.0
-          - toolset: clang
-            compiler: clang++-7
-            cxxstd: "17"
-            os: ubuntu-22.04
-            container: ubuntu:18.04
-            install:
-              - clang-7
-          - toolset: clang
-            compiler: clang++-8
-            cxxstd: "17"
-            os: ubuntu-22.04
-            container: ubuntu:18.04
-            install:
-              - clang-8
-              - g++-7
-            gcc_toolchain: 7
-          - toolset: clang
-            compiler: clang++-9
-            cxxstd: "14,17"
-            os: ubuntu-22.04
-            container: ubuntu:18.04
-            install:
-              - clang-9
-          - toolset: clang
-            compiler: clang++-10
-            cxxstd: "14,17"
-            os: ubuntu-20.04
-            install:
-              - clang-10
-          - toolset: clang
-            compiler: clang++-11
-            cxxstd: "14,17"
-            os: ubuntu-20.04
-            install:
-              - clang-11
-#          clang 12 tested on drone
-#          - toolset: clang
-#            compiler: clang++-12
-#            cxxstd: "17,20"
-#            os: ubuntu-22.04
-#            install:
-#              - clang-12
-#          - toolset: clang
-#            compiler: clang++-12
-#            cxxstd: "17,20"
-#            cxxflags: -stdlib=libc++
-#            linkflags: -stdlib=libc++
-#            os: ubuntu-20.04
-#            install:
-#              - clang-12
-#              - libc++-12-dev
-#              - libc++abi-12-dev
-#          - name: UBSAN
-#            toolset: clang
-#            compiler: clang++-12
-#            cxxstd: "17,20"
-#            cxxflags: -stdlib=libc++
-#            linkflags: -stdlib=libc++
-#            ubsan: 1
-#            os: ubuntu-20.04
-#            install:
-#              - clang-12
-#              - libc++-12-dev
-#              - libc++abi-12-dev
-
-          - toolset: clang
-            cxxstd: "11,14,17"
-            os: macos-11
-
-          - name: CMake tests
-            cmake_tests: 1
-            os: ubuntu-22.04
-
-    timeout-minutes: 120
-    runs-on: ${{matrix.os}}
-    container: ${{matrix.container}}
-
-    steps:
-      - name: Setup environment
-        run: |
-          if [ -f "/etc/debian_version" ]
-          then
-              echo "DEBIAN_FRONTEND=noninteractive" >> $GITHUB_ENV
-              export DEBIAN_FRONTEND=noninteractive
-          fi
-          if [ -n "${{matrix.container}}" ]
-          then
-              echo "GHA_CONTAINER=${{matrix.container}}" >> $GITHUB_ENV
-              if [ -f "/etc/debian_version" ]
-              then
-                  apt-get -o Acquire::Retries=$NET_RETRY_COUNT update
-                  apt-get -o Acquire::Retries=$NET_RETRY_COUNT install -y sudo software-properties-common tzdata wget curl apt-transport-https make apt-file unzip libssl-dev build-essential autotools-dev autoconf automake g++ libc++-helpers python ruby cpio gcc-multilib g++-multilib pkgconf python3 ccache libpython-dev
-          
-                  # install pip:
-                  python_version=$(python3 -c 'import sys; print("{0.major}.{0.minor}".format(sys.version_info))')
-                  if [[ ${python_version} =~ ^3\.[0-5]$ ]]; then
-                      true
-                  else
-                      apt-get install -y python3-distutils
-                  fi
-                  wget https://bootstrap.pypa.io/pip/$python_version/get-pip.py
-                  python3 get-pip.py
-          
-                  # install git:
-                  # apt-get install -y git
-                  apt-add-repository ppa:git-core/ppa
-                  apt-get -o Acquire::Retries=$NET_RETRY_COUNT update && apt-get -o Acquire::Retries=$NET_RETRY_COUNT install -y git
-          
-                  # install cmake:
-                  # apt-get -o Acquire::Retries=$NET_RETRY_COUNT install -y cmake
-                  sudo pip3 install cmake
-              fi
-          fi
-          git config --global pack.threads 0
-
-      - uses: actions/checkout@v2
-
-      - name: Install packages
-        if: matrix.install
-        run: |
-          SOURCE_KEYS=(${{join(matrix.source_keys, ' ')}})
-          SOURCES=(${{join(matrix.sources, ' ')}})
-          for key in "${SOURCE_KEYS[@]}"
-          do
-              for i in {1..$NET_RETRY_COUNT}
-              do
-                  wget -O - "$key" | sudo apt-key add - && break || sleep 2
-              done
-          done
-          if [ ${#SOURCES[@]} -gt 0 ]
-          then
-              APT_ADD_REPO_COMMON_ARGS=("-y")
-              APT_ADD_REPO_HAS_SOURCE_ARGS=0
-              SOFTWARE_PROPERTIES_VERSION="$(dpkg-query --showformat='${Version}' --show software-properties-common)"
-              if dpkg --compare-versions "$SOFTWARE_PROPERTIES_VERSION" ge "0.96.24.20"
-              then
-                  APT_ADD_REPO_COMMON_ARGS+=("-n")
-              fi
-              if dpkg --compare-versions "$SOFTWARE_PROPERTIES_VERSION" ge "0.98.10"
-              then
-                  APT_ADD_REPO_HAS_SOURCE_ARGS=1
-              fi
-              for source in "${SOURCES[@]}"
-              do
-                  for i in {1..$NET_RETRY_COUNT}
-                  do
-                      APT_ADD_REPO_ARGS=("${APT_ADD_REPO_COMMON_ARGS[@]}")
-                      if [ $APT_ADD_REPO_HAS_SOURCE_ARGS -ne 0 ]
-                      then
-                          case "$source" in
-                          "ppa:"*)
-                              APT_ADD_REPO_ARGS+=("-P")
-                              ;;
-                          "deb "*)
-                              APT_ADD_REPO_ARGS+=("-S")
-                              ;;
-                          *)
-                              APT_ADD_REPO_ARGS+=("-U")
-                              ;;
-                          esac
-                      fi
-                      APT_ADD_REPO_ARGS+=("$source")
-                      sudo -E apt-add-repository "${APT_ADD_REPO_ARGS[@]}" && break || sleep 2
-                  done
-              done
-          fi
-          sudo apt-get -o Acquire::Retries=$NET_RETRY_COUNT update
-          sudo apt-get -o Acquire::Retries=$NET_RETRY_COUNT install -y ${{join(matrix.install, ' ')}}
-
-      - name: Setup GCC Toolchain
-        if: matrix.gcc_toolchain
-        run: |
-          GCC_TOOLCHAIN_ROOT="$HOME/gcc-toolchain"
-          echo "GCC_TOOLCHAIN_ROOT=\"$GCC_TOOLCHAIN_ROOT\"" >> $GITHUB_ENV
-          MULTIARCH_TRIPLET="$(dpkg-architecture -qDEB_HOST_MULTIARCH)"
-          mkdir -p "$GCC_TOOLCHAIN_ROOT"
-          ln -s /usr/include "$GCC_TOOLCHAIN_ROOT/include"
-          ln -s /usr/bin "$GCC_TOOLCHAIN_ROOT/bin"
-          mkdir -p "$GCC_TOOLCHAIN_ROOT/lib/gcc/$MULTIARCH_TRIPLET"
-          ln -s "/usr/lib/gcc/$MULTIARCH_TRIPLET/${{matrix.gcc_toolchain}}" "$GCC_TOOLCHAIN_ROOT/lib/gcc/$MULTIARCH_TRIPLET/${{matrix.gcc_toolchain}}"
-
-      - name: Setup Boost
-        run: |
-          echo GITHUB_REPOSITORY: $GITHUB_REPOSITORY
-          LIBRARY=${GITHUB_REPOSITORY#*/}
-          echo LIBRARY: $LIBRARY
-          echo "LIBRARY=$LIBRARY" >> $GITHUB_ENV
-          echo GITHUB_BASE_REF: $GITHUB_BASE_REF
-          echo GITHUB_REF: $GITHUB_REF
-          REF=${GITHUB_BASE_REF:-$GITHUB_REF}
-          REF=${REF#refs/heads/}
-          echo REF: $REF
-          BOOST_BRANCH=develop && [ "$REF" == "master" ] && BOOST_BRANCH=master || true
-          echo BOOST_BRANCH: $BOOST_BRANCH
-          BUILD_JOBS=$((nproc || sysctl -n hw.ncpu) 2> /dev/null)
-          echo "BUILD_JOBS=$BUILD_JOBS" >> $GITHUB_ENV
-          echo "CMAKE_BUILD_PARALLEL_LEVEL=$BUILD_JOBS" >> $GITHUB_ENV
-          DEPINST_ARGS=()
-          GIT_VERSION="$(git --version | sed -e 's/git version //')"
-          if $(dpkg --compare-versions "$GIT_VERSION" ge 2.8.0)
-          then
-              DEPINST_ARGS+=("--git_args" "--jobs $GIT_FETCH_JOBS")
-          fi
-          cd ..
-          git clone -b "$BOOST_BRANCH" --depth 1 "https://github.com/boostorg/boost.git" "boost-root"
-          
-          cd boost-root
-          # mkdir -p libs/$LIBRARY
-          # cp -r $GITHUB_WORKSPACE/* libs/$LIBRARY
-          # git submodule update --init tools/boostdep
-          git submodule update --init --recursive
-          mkdir -p libs/$SELF
-          cp -r $GITHUB_WORKSPACE/* libs/$SELF
-          
-          DEPINST_ARGS+=("$LIBRARY")
-          python tools/boostdep/depinst/depinst.py "${DEPINST_ARGS[@]}"
-          if [ -z "${{matrix.cmake_tests}}" ]
-          then
-              ./bootstrap.sh
-              ./b2 headers
-              if [ -n "${{matrix.compiler}}" -o -n "$GCC_TOOLCHAIN_ROOT" ]
-              then
-                  echo -n "using ${{matrix.toolset}} : : ${{matrix.compiler}}" > ~/user-config.jam
-                  if [ -n "$GCC_TOOLCHAIN_ROOT" ]
-                  then
-                      echo -n " : <compileflags>\"--gcc-toolchain=$GCC_TOOLCHAIN_ROOT\" <linkflags>\"--gcc-toolchain=$GCC_TOOLCHAIN_ROOT\"" >> ~/user-config.jam
-                  fi
-                  echo " ;" >> ~/user-config.jam
-              fi
-          fi
-
-      - name: Run tests
-        if: matrix.cmake_tests == ''
-        run: |
-          cd ../boost-root
-          B2_ARGS=("-j" "$BUILD_JOBS" "toolset=${{matrix.toolset}}" "cxxstd=${{matrix.cxxstd}}")
-          if [ -n "${{matrix.build_variant}}" ]
-          then
-              B2_ARGS+=("variant=${{matrix.build_variant}}")
-          else
-              B2_ARGS+=("variant=$DEFAULT_BUILD_VARIANT")
-          fi
-          if [ -n "${{matrix.threading}}" ]
-          then
-              B2_ARGS+=("threading=${{matrix.threading}}")
-          fi
-          if [ -n "${{matrix.ubsan}}" ]
-          then
-              export UBSAN_OPTIONS="print_stacktrace=1"
-              B2_ARGS+=("cxxflags=-fsanitize=undefined -fno-sanitize-recover=undefined" "linkflags=-fsanitize=undefined -fuse-ld=gold" "define=UBSAN=1" "debug-symbols=on" "visibility=global")
-          fi
-          if [ -n "${{matrix.cxxflags}}" ]
-          then
-              B2_ARGS+=("cxxflags=${{matrix.cxxflags}}")
-          fi
-          if [ -n "${{matrix.linkflags}}" ]
-          then
-              B2_ARGS+=("linkflags=${{matrix.linkflags}}")
-          fi
-          B2_ARGS+=("libs/$LIBRARY/test")
-          ./b2 "${B2_ARGS[@]}"
-
-#      - name: Run CMake tests
-#        if: matrix.cmake_tests != ''
-#        run: |
-#          cd ../boost-root
-#          git submodule update --init --recursive
-#          cd libs/$LIBRARY
-#          mkdir __build__ && cd __build__
-#          cmake -DCMAKE_INSTALL_PREFIX=~/.local ..
-#          cmake --build . --target install
-
-  windows:
-    strategy:
-      fail-fast: false
-      matrix:
-        include:
-          #- toolset: msvc-14.1
-          #  cxxstd: "14,17,latest"
-          #  addrmd: 32,64
-          #  os: windows-2016
-          - toolset: msvc-14.2
-            cxxstd: "14,17"
-            addrmd: 32,64
-            os: windows-2019
-          - toolset: msvc-14.3
-            cxxstd: "17,20"
-            addrmd: 32,64
-            os: windows-2022
-    #          - toolset: gcc
-    #            cxxstd: "11,14,17"
-    #            addrmd: 64
-    #            os: windows-2019
-
-    runs-on: ${{matrix.os}}
-
-    steps:
-      - uses: actions/checkout@v2
-
-      - name: Setup Boost
-        shell: cmd
-        run: |
-          echo GITHUB_REPOSITORY: %GITHUB_REPOSITORY%
-          for /f %%i in ("%GITHUB_REPOSITORY%") do set LIBRARY=%%~nxi
-          echo LIBRARY: %LIBRARY%
-          echo LIBRARY=%LIBRARY%>>%GITHUB_ENV%
-          echo GITHUB_BASE_REF: %GITHUB_BASE_REF%
-          echo GITHUB_REF: %GITHUB_REF%
-          if "%GITHUB_BASE_REF%" == "" set GITHUB_BASE_REF=%GITHUB_REF%
-          set BOOST_BRANCH=develop
-          for /f %%i in ("%GITHUB_BASE_REF%") do if "%%~nxi" == "master" set BOOST_BRANCH=master
-          echo BOOST_BRANCH: %BOOST_BRANCH%
-          cd ..
-          git clone -b %BOOST_BRANCH% --depth 1 https://github.com/boostorg/boost.git boost-root
-          cd boost-root
-          xcopy /s /e /q %GITHUB_WORKSPACE% libs\%LIBRARY%\
-          git submodule update --init tools/boostdep
-          python tools/boostdep/depinst/depinst.py --git_args "--jobs %GIT_FETCH_JOBS%" %LIBRARY%
-          cmd /c bootstrap
-          b2 -d0 headers
-
-      - name: Run tests
-        shell: cmd
-        run: |
-          cd ../boost-root
-          b2 -j %NUMBER_OF_PROCESSORS% libs/%LIBRARY%/test toolset=${{matrix.toolset}} cxxstd=${{matrix.cxxstd}} address-model=${{matrix.addrmd}} variant=debug,release
-
-  CMake:
-    defaults:
-      run:
-        shell: bash
-
-    strategy:
-      fail-fast: false
-      matrix:
-        include:
-          - { os: ubuntu-22.04, build_shared: ON,  build_type: Debug, generator: 'Unix Makefiles' }
-          - { os: ubuntu-22.04, build_shared: OFF, build_type: Debug, generator: 'Unix Makefiles' }
-          - { os: windows-2019, build_shared: ON,  build_type: Debug, generator: 'Visual Studio 16 2019' }
-          - { os: windows-2019, build_shared: OFF, build_type: Debug, generator: 'Visual Studio 16 2019' }
-
-    timeout-minutes: 120
-    runs-on: ${{matrix.os}}
-
-    steps:
-      - uses: actions/checkout@v2
-      - name: Fetch Boost.CI
-        uses: actions/checkout@v2
-        with:
-          repository: boostorg/boost-ci
-          ref: master
-          path: boost-ci-cloned
-
-      - name: Get CI scripts folder
-        run: |
-          # Copy ci folder if not testing Boost.CI
-          [[ "$GITHUB_REPOSITORY" =~ "boost-ci" ]] || cp -r boost-ci-cloned/ci .
-          rm -rf boost-ci-cloned
-      - name: Setup Boost
-        env: {B2_DONT_BOOTSTRAP: 1}
-        run: source ci/github/install.sh
-
-#      - name: Run CMake tests
-#        run: |
-#          cd "$BOOST_ROOT"
-#          mkdir __build_cmake_test__ && cd __build_cmake_test__
-#          cmake -G "${{matrix.generator}}" -DCMAKE_BUILD_TYPE=${{matrix.build_type}} -DBOOST_INCLUDE_LIBRARIES=$SELF -DBUILD_SHARED_LIBS=${{matrix.build_shared}} -DBUILD_TESTING=ON -DBoost_VERBOSE=ON ..
-#          cmake --build . --target tests boost_url_tests boost_url_limits boost_url_extra --config ${{matrix.build_type}}
-#          ctest --output-on-failure --build-config ${{matrix.build_type}}
-#      - name: Run CMake subdir tests
-#        run: |
-#          cmake_test_folder="$BOOST_ROOT/libs/$SELF/test/cmake_test" # New unified folder
-#          [ -d "$cmake_test_folder" ] || cmake_test_folder="$BOOST_ROOT/libs/$SELF/test/cmake_subdir_test"
-#          cd "$cmake_test_folder"
-#          mkdir __build_cmake_subdir_test__ && cd __build_cmake_subdir_test__
-#          cmake -G "${{matrix.generator}}" -DBOOST_CI_INSTALL_TEST=OFF -DCMAKE_BUILD_TYPE=${{matrix.build_type}} -DBUILD_SHARED_LIBS=${{matrix.build_shared}} ..
-#          cmake --build . --config ${{matrix.build_type}}
-#          ctest --output-on-failure --build-config ${{matrix.build_type}}
-#      - name: Install Library
-#        run: |
-#          cd "$BOOST_ROOT"
-#          mkdir __build_cmake_install_test__ && cd __build_cmake_install_test__
-#          cmake -G "${{matrix.generator}}" -DCMAKE_BUILD_TYPE=${{matrix.build_type}} -DBOOST_INCLUDE_LIBRARIES=$SELF -DBUILD_SHARED_LIBS=${{matrix.build_shared}} -DCMAKE_INSTALL_PREFIX=~/.local -DBoost_VERBOSE=ON -DBoost_DEBUG=ON ..
-#          cmake --build . --target install --config ${{matrix.build_type}}
-#      - name: Run CMake install tests
-#        run: |
-#          cmake_test_folder="$BOOST_ROOT/libs/$SELF/test/cmake_test" # New unified folder
-#          [ -d "$cmake_test_folder" ] || cmake_test_folder="$BOOST_ROOT/libs/$SELF/test/cmake_install_test"
-#          cd "$cmake_test_folder"
-#          mkdir __build_cmake_install_test__ && cd __build_cmake_install_test__
-#          cmake -G "${{matrix.generator}}" -DBOOST_CI_INSTALL_TEST=ON -DCMAKE_BUILD_TYPE=${{matrix.build_type}} -DBUILD_SHARED_LIBS=${{matrix.build_shared}} -DCMAKE_PREFIX_PATH=~/.local ..
-#          cmake --build . --config ${{matrix.build_type}}
-#          ctest --output-on-failure --build-config ${{matrix.build_type}}
+  call-boost-ci:
+    name: Run Boost.CI
+    uses: boostorg/boost-ci/.github/workflows/reusable.yml@master
+    with:
+      exclude_cxxstd: '98,03,0x'
+      enable_pr_coverage: false
+      enable_multiarch: false
+    # Example of customization:
+    # with:
+    #   enable_reflection: true
+    #   enable_windows: false
+    # secrets:
+    #   CODECOV_TOKEN: ${{ secrets.CODECOV_TOKEN }}
+    #   COVERITY_SCAN_NOTIFICATION_EMAIL: ${{ secrets.COVERITY_SCAN_NOTIFICATION_EMAIL }}
+    #   COVERITY_SCAN_TOKEN: ${{ secrets.COVERITY_SCAN_TOKEN }}

.github/workflows/example.yml

@@ -0,0 +1,156 @@
+#
+# Copyright (c) 2025 Gennaro Prota (gennaro dot prota at gmail dot com)
+#
+# Distributed under the Boost Software License, Version 1.0. (See accompanying
+# file LICENSE_1_0.txt or copy at https://www.boost.org/LICENSE_1_0.txt)
+#
+# Official repository: https://github.com/boostorg/static_string
+#
+
+name: Example (basic_static_cstring)
+
+on:
+  pull_request:
+  push:
+    branches:
+      - master
+      - develop
+      - bugfix/**
+      - feature/**
+      - fix/**
+      - github/**
+      - pr/**
+    paths-ignore:
+      - LICENSE
+      - meta/**
+      - README.md
+
+jobs:
+  linux:
+    runs-on: ubuntu-24.04
+    strategy:
+      fail-fast: false
+      matrix:
+        include:
+          - { toolset: gcc-13,   cxxstd: '20,23' }
+          - { toolset: gcc-14,   cxxstd: '20,23,26' }
+          - { toolset: clang-17, cxxstd: '20,23' }
+          - { toolset: clang-18, cxxstd: '20,23,26' }
+
+    steps:
+      - name: Checkout Boost super-project
+        uses: actions/checkout@v4
+        with:
+          repository: boostorg/boost
+          ref: develop
+          fetch-depth: 0
+
+      - name: Checkout this library
+        uses: actions/checkout@v4
+        with:
+          path: libs/static_string
+          fetch-depth: 0
+
+      - name: Initialize Boost submodules
+        run: |
+          git submodule update --init tools/boostdep
+          python tools/boostdep/depinst/depinst.py --git_args '--jobs 4' static_string
+
+      - name: Bootstrap b2
+        run: ./bootstrap.sh
+
+      - name: Generate Boost headers
+        run: ./b2 headers
+
+      - name: Build and run example tests
+        run: |
+          ./b2 libs/static_string/example/static_cstring \
+            toolset=${{ matrix.toolset }} \
+            cxxstd=${{ matrix.cxxstd }} \
+            variant=debug,release \
+            -j$(nproc)
+
+  macos:
+    runs-on: macos-14
+    strategy:
+      fail-fast: false
+      matrix:
+        include:
+          - { toolset: clang, cxxstd: '20,23' }
+
+    steps:
+      - name: Checkout Boost super-project
+        uses: actions/checkout@v4
+        with:
+          repository: boostorg/boost
+          ref: develop
+          fetch-depth: 0
+
+      - name: Checkout this library
+        uses: actions/checkout@v4
+        with:
+          path: libs/static_string
+          fetch-depth: 0
+
+      - name: Initialize Boost submodules
+        run: |
+          git submodule update --init tools/boostdep
+          python3 tools/boostdep/depinst/depinst.py --git_args '--jobs 4' static_string
+
+      - name: Bootstrap b2
+        run: ./bootstrap.sh
+
+      - name: Generate Boost headers
+        run: ./b2 headers
+
+      - name: Build and run example tests
+        run: |
+          ./b2 libs/static_string/example/static_cstring \
+            toolset=${{ matrix.toolset }} \
+            cxxstd=${{ matrix.cxxstd }} \
+            variant=debug,release \
+            -j$(sysctl -n hw.ncpu)
+
+  windows:
+    runs-on: windows-2022
+    strategy:
+      fail-fast: false
+      matrix:
+        include:
+          - { toolset: msvc-14.3, cxxstd: '20,latest' }
+
+    steps:
+      - name: Checkout Boost super-project
+        uses: actions/checkout@v4
+        with:
+          repository: boostorg/boost
+          ref: develop
+          fetch-depth: 0
+
+      - name: Checkout this library
+        uses: actions/checkout@v4
+        with:
+          path: libs/static_string
+          fetch-depth: 0
+
+      - name: Initialize Boost submodules
+        run: |
+          git submodule update --init tools/boostdep
+          python tools/boostdep/depinst/depinst.py --git_args '--jobs 4' static_string
+
+      - name: Bootstrap b2
+        run: .\bootstrap.bat
+        shell: cmd
+
+      - name: Generate Boost headers
+        run: .\b2 headers
+        shell: cmd
+
+      - name: Build and run example tests
+        run: |
+          .\b2 libs/static_string/example/static_cstring ^
+            toolset=${{ matrix.toolset }} ^
+            cxxstd=${{ matrix.cxxstd }} ^
+            variant=debug,release ^
+            address-model=64
+        shell: cmd

.gitignore

@@ -1,8 +1,15 @@
 bin/
 bin64/
+build/
 
 # Because of CMake and VS2017
 Win32/
 x64/
 .vs/
-out/
+out/
+
+# VS CMake settings
+/CMakeSettings.json
+# CMake presets
+/CMakePresets.json
+/CMakeUserPresets.json

CMakeLists.txt

@@ -7,7 +7,7 @@
 # Official repository: https://github.com/boostorg/static_string
 #
 
-cmake_minimum_required(VERSION 3.5...3.16)
+cmake_minimum_required(VERSION 3.8...3.16)
 
 project(boost_static_string VERSION "${BOOST_SUPERPROJECT_VERSION}" LANGUAGES CXX)
 
@@ -23,7 +23,7 @@ endif ()
 # Options
 if (NOT BOOST_SUPERPROJECT_VERSION)
     option(BOOST_STATIC_STRING_INSTALL "Install boost::static_string files" ${BOOST_STATIC_STRING_IS_ROOT})
-    option(BOOST_STATIC_STRING_BUILD_TESTS "Build boost::static_string tests" ${BUILD_TESTING})
+    option(BOOST_STATIC_STRING_BUILD_TESTS "Build boost::static_string tests" OFF)
 else ()
     set(BOOST_STATIC_STRING_BUILD_TESTS ${BUILD_TESTING})
 endif ()
@@ -45,7 +45,7 @@ if (BOOST_STATIC_STRING_FIND_PACKAGE_BOOST)
     find_package(Boost 1.78.0 REQUIRED COMPONENTS container)
 elseif (BOOST_STATIC_STRING_IS_ROOT)
     set(BOOST_STATIC_STRING_UNIT_TEST_LIBRARIES core)
-    set(BOOST_INCLUDE_LIBRARIES static_string assert container_hash static_assert throw_exception utility ${BOOST_STATIC_STRING_UNIT_TEST_LIBRARIES})
+    set(BOOST_INCLUDE_LIBRARIES static_string assert container_hash throw_exception utility ${BOOST_STATIC_STRING_UNIT_TEST_LIBRARIES})
     set(BOOST_EXCLUDE_LIBRARIES static_string)
     set(CMAKE_FOLDER Dependencies)
     add_subdirectory(../.. Dependencies/boost EXCLUDE_FROM_ALL)
@@ -90,7 +90,6 @@ else ()
             Boost::assert
             Boost::container_hash
             Boost::core
-            Boost::static_assert
             Boost::throw_exception
             Boost::utility
             )
@@ -112,7 +111,7 @@ if (BOOST_STATIC_STRING_INSTALL AND NOT BOOST_SUPERPROJECT_VERSION)
 endif ()
 
 
-if (BOOST_STATIC_STRING_BUILD_TESTS)
+if (BUILD_TESTING OR BOOST_STATIC_STRING_BUILD_TESTS)
     add_subdirectory(test)
 endif ()
 

Jamfile

@@ -1,10 +0,0 @@
-#
-# Copyright (c) 2019 Vinnie Falco (vinnie dot falco at gmail dot com)
-#
-# Distributed under the Boost Software License, Version 1.0. (See accompanying
-# file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
-#
-# Official repository: https://github.com/boostorg/static_string
-#
-
-build-project test ;

README.md

@@ -1,9 +1,9 @@
 # Boost.StaticString
 
-Branch          | Travis | Appveyor | Azure Pipelines | codecov.io | Docs | Matrix |
+Branch          | GHA CI | Appveyor | Azure Pipelines | codecov.io | Docs | Matrix |
 :-------------: | ------ | -------- | --------------- | ---------- | ---- | ------ |
-[`master`](https://github.com/boostorg/static_string/tree/master) | [![Build Status](https://travis-ci.org/boostorg/static_string.svg?branch=master)](https://travis-ci.org/boostorg/static_string) | [![Build status](https://ci.appveyor.com/api/projects/status/64es4wg4w7mc5wn2/branch/master?svg=true)](https://ci.appveyor.com/project/sdkrystian/static-string/branch/master) | [![Build Status](https://krystiands.visualstudio.com/static_string/_apis/build/status/Boost.StaticString?branchName=master)](https://krystiands.visualstudio.com/static_string/_build/latest?definitionId=3&branchName=master) | [![codecov](https://codecov.io/gh/boostorg/static_string/branch/master/graph/badge.svg)](https://codecov.io/gh/boostorg/static_string/branch/master) | [![Documentation](https://img.shields.io/badge/docs-master-brightgreen.svg)](http://www.boost.org/doc/libs/release/libs/static_string) | [![Matrix](https://img.shields.io/badge/matrix-master-brightgreen.svg)](http://www.boost.org/development/tests/master/developer/static_string.html)
-[`develop`](https://github.com/boostorg/static_string/tree/develop) | [![Build Status](https://travis-ci.org/boostorg/static_string.svg?branch=develop)](https://travis-ci.org/boostorg/static_string) | [![Build status](https://ci.appveyor.com/api/projects/status/64es4wg4w7mc5wn2/branch/develop?svg=true)](https://ci.appveyor.com/project/sdkrystian/static-string/branch/develop) | [![Build Status](https://krystiands.visualstudio.com/static_string/_apis/build/status/Boost.StaticString?branchName=develop)](https://krystiands.visualstudio.com/static_string/_build/latest?definitionId=3&branchName=develop) | [![codecov](https://codecov.io/gh/boostorg/static_string/branch/develop/graph/badge.svg)](https://codecov.io/gh/boostorg/static_string/branch/develop) | [![Documentation](https://img.shields.io/badge/docs-develop-brightgreen.svg)](http://www.boost.org/doc/libs/develop/libs/static_string) | [![Matrix](https://img.shields.io/badge/matrix-develop-brightgreen.svg)](http://www.boost.org/development/tests/develop/developer/static_string.html)
+[`master`](https://github.com/boostorg/static_string/tree/master) | [![Build Status](https://github.com/boostorg/static_string/actions/workflows/ci.yml/badge.svg?branch=master)](https://github.com/boostorg/static_string/actions?query=branch:master) | [![Build status](https://ci.appveyor.com/api/projects/status/64es4wg4w7mc5wn2/branch/master?svg=true)](https://ci.appveyor.com/project/sdkrystian/static-string/branch/master) | [![Build Status](https://krystiands.visualstudio.com/static_string/_apis/build/status/Boost.StaticString?branchName=master)](https://krystiands.visualstudio.com/static_string/_build/latest?definitionId=3&branchName=master) | [![codecov](https://codecov.io/gh/boostorg/static_string/branch/master/graph/badge.svg)](https://codecov.io/gh/boostorg/static_string/branch/master) | [![Documentation](https://img.shields.io/badge/docs-master-brightgreen.svg)](http://www.boost.org/doc/libs/release/libs/static_string) | [![Matrix](https://img.shields.io/badge/matrix-master-brightgreen.svg)](https://regression.boost.org/master/developer/static_string.html)
+[`develop`](https://github.com/boostorg/static_string/tree/develop) | [![Build Status](https://github.com/boostorg/static_string/actions/workflows/ci.yml/badge.svg?branch=develop)](https://github.com/boostorg/static_string/actions?query=branch:develop) | [![Build status](https://ci.appveyor.com/api/projects/status/64es4wg4w7mc5wn2/branch/develop?svg=true)](https://ci.appveyor.com/project/sdkrystian/static-string/branch/develop) | [![Build Status](https://krystiands.visualstudio.com/static_string/_apis/build/status/Boost.StaticString?branchName=develop)](https://krystiands.visualstudio.com/static_string/_build/latest?definitionId=3&branchName=develop) | [![codecov](https://codecov.io/gh/boostorg/static_string/branch/develop/graph/badge.svg)](https://codecov.io/gh/boostorg/static_string/branch/develop) | [![Documentation](https://img.shields.io/badge/docs-develop-brightgreen.svg)](http://www.boost.org/doc/libs/develop/libs/static_string) | [![Matrix](https://img.shields.io/badge/matrix-develop-brightgreen.svg)](https://regression.boost.org/develop/developer/static_string.html)
 
 ## Introduction
 

build.jam

@@ -0,0 +1,27 @@
+# Copyright René Ferdinand Rivera Morell 2023-2024
+# Distributed under the Boost Software License, Version 1.0.
+# (See accompanying file LICENSE_1_0.txt or copy at
+# http://www.boost.org/LICENSE_1_0.txt)
+
+require-b2 5.2 ;
+
+constant boost_dependencies :
+    /boost/assert//boost_assert
+    /boost/config//boost_config
+    /boost/container_hash//boost_container_hash
+    /boost/core//boost_core
+    /boost/throw_exception//boost_throw_exception
+    /boost/utility//boost_utility ;
+
+project /boost/static_string
+    ;
+
+explicit
+    [ alias boost_static_string : : :
+        : <include>include <library>$(boost_dependencies) ]
+    [ alias all : boost_static_string test ]
+    ;
+
+call-if : boost-library static_string
+    ;
+

doc/Jamfile

@@ -9,21 +9,21 @@
 
 project static_string/doc ;
 
-import boostbook ;
-import type ;
-import os ;
-import ../../../tools/docca/docca.jam ;
+import-search /boost/docca ;
 
-docca.reference reference.qbk
+import docca ;
+import path ;
+import os ;
+
+local include-prefix = [ path.root $(__file__:D) [ path.pwd ] ] ;
+include-prefix = [ path.native $(include-prefix:D)/include ] ;
+
+docca.pyreference reference.qbk
     :
-        xsl/custom-overrides.xsl
         [ glob-tree-ex ../include/boost/static_string : *.hpp *.ipp : detail impl ]
+        externals.hpp
     :
-        <doxygen:param>PROJECT_NAME=StaticString
-        <doxygen:param>PROJECT_BRIEF="Static String Library"
         <doxygen:param>ALIASES="esafe=\"@par Exception Safety\""
-        <doxygen:param>FILE_PATTERNS=
-        <doxygen:param>EXAMPLE_PATTERNS=
         <doxygen:param>DISTRIBUTE_GROUP_DOC=YES
         <doxygen:param>MACRO_EXPANSION=YES
         <doxygen:param>EXPAND_ONLY_PREDEF=YES
@@ -40,19 +40,17 @@ docca.reference reference.qbk
         <doxygen:param>EXTRACT_ALL=YES
         <doxygen:param>EXTRACT_PRIVATE=YES
         <doxygen:param>EXTRACT_LOCAL_CLASSES=NO
-        <doxygen:param>SHOW_INCLUDE_FILES=NO
         <doxygen:param>INLINE_INFO=NO
         <doxygen:param>SORT_MEMBER_DOCS=NO
         <doxygen:param>SORT_MEMBERS_CTORS_1ST=YES
-        <doxygen:param>SHOW_USED_FILES=NO
-        <doxygen:param>SHOW_FILES=NO
-        <doxygen:param>SHOW_NAMESPACES=NO
-        <doxygen:param>CLASS_DIAGRAMS=NO
+        <doxygen:param>STRIP_FROM_PATH=$(include-prefix)
 
         # <doxygen:param>ALLOW_UNICODE_NAMES=NO
         # <doxygen:param>GROUP_NESTED_COMPOUNDS=NO
         # <doxygen:param>HIDE_COMPOUND_REFERENCE=NO
         # <doxygen:param>WARN_AS_ERROR=NO
+
+        <docca:config>config.json
     ;
 
 #-------------------------------------------------------------------------------

doc/config.json

@@ -0,0 +1,12 @@
+{
+    "include_private": false,
+    "legacy_behavior": false,
+    "external_marker": "!EXTERNAL!",
+    "link_prefix": "static_string.ref.",
+    "default_namespace": "boost::static_strings",
+    "allowed_prefixes": ["boost::static_strings::", "std::"],
+    "convenience_header": "boost/static_string.hpp",
+    "replace_strings": {
+        "__see_below__": "``['see-below]``"
+    }
+}

doc/externals.hpp

@@ -0,0 +1,64 @@
+#pragma once
+
+namespace boost {
+
+/// !EXTERNAL!
+///
+/// @see https://www.boost.org/doc/libs/release/libs/utility/doc/html/utility/utilities/string_view.html
+template <class T, class Traits>
+struct basic_string_view {};
+
+} // namespace boost
+
+namespace std {
+
+/// !EXTERNAL!
+///
+/// @see https://en.cppreference.com/w/cpp/iterator/reverse_iterator
+template <class T>
+struct reverse_iterator {};
+
+/// !EXTERNAL!
+///
+/// @see https://en.cppreference.com/w/cpp/types/size_t
+struct size_t {};
+
+/// !EXTERNAL!
+///
+/// @see https://en.cppreference.com/w/cpp/types/integer
+struct uint64_t {};
+
+/// !EXTERNAL!
+///
+/// @see https://en.cppreference.com/w/cpp/types/integer
+struct int64_t {};
+
+/// !EXTERNAL!
+///
+/// @see https://en.cppreference.com/w/cpp/types/nullptr_t
+struct nullptr_t {};
+
+/// !EXTERNAL!
+///
+/// @see https://en.cppreference.com/w/cpp/types/ptrdiff_t
+struct ptrdiff_t {};
+
+/// !EXTERNAL!
+///
+/// @see https://en.cppreference.com/w/cpp/utility/initializer_list
+template <class T>
+struct initializer_list {};
+
+/// !EXTERNAL!
+///
+/// @see https://en.cppreference.com/w/cpp/io/basic_ostream
+template <class T, class Traits>
+struct basic_ostream {};
+
+/// !EXTERNAL!
+///
+/// @see https://en.cppreference.com/w/cpp/types/numeric_limits
+template <class T>
+struct numeric_limits {};
+
+} // namespace std

doc/xsl/custom-overrides.xsl

@@ -1,11 +0,0 @@
-<xsl:stylesheet version="3.0"
-  xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
-  xmlns:xs="http://www.w3.org/2001/XMLSchema"
-  exclude-result-prefixes="xs"
-  expand-text="yes">
-
-  <xsl:variable name="doc-ref" select="'static_string.ref'"/>
-  <xsl:variable name="doc-ns" select="'boost::static_strings'"/>
-  <xsl:variable name="include-private-members" select="false()"/>
-
-</xsl:stylesheet>

example/static_cstring/Jamfile

@@ -0,0 +1,19 @@
+#
+# Copyright (c) 2025 Gennaro Prota (gennaro dot prota at gmail dot com)
+#
+# Distributed under the Boost Software License, Version 1.0. (See accompanying
+# file LICENSE_1_0.txt or copy at https://www.boost.org/LICENSE_1_0.txt)
+#
+# Official repository: https://github.com/boostorg/static_string
+#
+
+import testing ;
+
+project
+  : requirements
+    <include>../../include
+    <warnings>extra
+    <cxxstd>20
+  ;
+
+run static_cstring_test.cpp ;

example/static_cstring/README.md

@@ -0,0 +1,13 @@
+This directory contains an experimental implementation of `basic_static_cstring`, which differs from `basic_static_string` in the following ways:
+
+|                     | `basic_static_cstring` | `basic_static_string` |
+|---------------------|------------------------|-----------------------|
+| Layout              | `sizeof == N + 1`      | Has size member       |
+| Embedded NULs       | Not supported          | Supported             |
+| Trivially copyable  | Yes                    | No                    |
+
+Additionally, when `N <= UCHAR_MAX`, `basic_static_cstring` employs an optimization that avoids calling `std::strlen()` to compute the size.
+
+This work stems from [boostorg/static_string#23](https://github.com/boostorg/static_string/issues/23).
+
+If you believe `basic_static_cstring` should become part of the public API, please share your feedback on the Boost mailing list.

example/static_cstring/static_cstring.hpp

@@ -0,0 +1,441 @@
+//
+// Copyright (c) 2025 Gennaro Prota (gennaro dot prota at gmail dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at https://www.boost.org/LICENSE_1_0.txt)
+//
+// Official repository: https://github.com/boostorg/static_string
+//
+
+#ifndef BOOST_STATIC_STRING_STATIC_CSTRING_HPP
+#define BOOST_STATIC_STRING_STATIC_CSTRING_HPP
+
+#include <boost/static_string/config.hpp>
+#include <algorithm>
+#include <climits>
+#include <cstddef>
+#include <ostream>
+#include <string>
+#include <string_view>
+#include <stdexcept>
+#include <type_traits>
+
+namespace boost {
+namespace static_strings {
+
+namespace detail {
+
+// Primary template: No remaining-capacity trick; uses traits::length() for length.
+template<std::size_t N, typename CharT, typename Traits, bool UseRemaining>
+class static_cstring_base
+{
+public:
+    using traits_type = Traits;
+    using value_type = CharT;
+    using size_type = std::size_t;
+
+    value_type data_[N + 1]{};
+
+    constexpr size_type get_size() const noexcept
+    {
+        return traits_type::length(data_);
+    }
+
+    constexpr void set_size(size_type sz) noexcept
+    {
+        data_[sz] = value_type{};
+    }
+
+    // Defaulted comparisons for structural type support.
+    constexpr bool operator==(const static_cstring_base&) const noexcept = default;
+    constexpr auto operator<=>(const static_cstring_base&) const noexcept = default;
+};
+
+// Specialization for N <= UCHAR_MAX: Uses remaining-capacity trick.
+template<std::size_t N, typename CharT, typename Traits>
+class static_cstring_base<N, CharT, Traits, true>
+{
+public:
+    using traits_type = Traits;
+    using value_type = CharT;
+    using size_type = std::size_t;
+
+    value_type data_[N + 1]{};
+
+    constexpr size_type get_size() const noexcept
+    {
+        return N - static_cast<unsigned char>(data_[N]);
+    }
+
+    constexpr void set_size(size_type sz) noexcept
+    {
+        data_[sz] = value_type{};
+        data_[N] = static_cast<value_type>(N - sz);
+    }
+
+    // Defaulted comparisons for structural type support.
+    constexpr bool operator==(const static_cstring_base&) const noexcept = default;
+    constexpr auto operator<=>(const static_cstring_base&) const noexcept = default;
+};
+
+} // namespace detail
+
+template<std::size_t N, typename CharT = char, typename Traits = std::char_traits<CharT>>
+class basic_static_cstring
+    : public detail::static_cstring_base<N, CharT, Traits, (N <= UCHAR_MAX)>
+{
+public:
+    using base = detail::static_cstring_base<N, CharT, Traits, (N <= UCHAR_MAX)>;
+    using base::data_;
+    using base::get_size;
+    using base::set_size;
+
+    // Member types
+    using traits_type     = Traits;
+    using value_type      = CharT;
+    using size_type       = std::size_t;
+    using difference_type = std::ptrdiff_t;
+    using reference       = value_type&;
+    using const_reference = const value_type&;
+    using pointer         = value_type*;
+    using const_pointer   = const value_type*;
+    using iterator        = pointer;
+    using const_iterator  = const_pointer;
+
+    static constexpr size_type npos = static_cast<size_type>(-1);
+    static constexpr size_type static_capacity = N;
+
+    // Constructors.
+    constexpr basic_static_cstring() noexcept
+    {
+        set_size(0);
+    }
+
+    constexpr basic_static_cstring(const CharT* s)
+    {
+        assign(s);
+    }
+
+    constexpr basic_static_cstring(const CharT* s, size_type count)
+    {
+        assign(s, count);
+    }
+
+    constexpr basic_static_cstring(size_type count, CharT ch)
+    {
+        assign(count, ch);
+    }
+
+    template<std::size_t M>
+    constexpr basic_static_cstring(const CharT (&arr)[M])
+    {
+        static_assert(M <= N + 1, "String literal too long for static_cstring");
+        assign(arr, M - 1);
+    }
+
+    constexpr size_type size() const noexcept
+    {
+        return get_size();
+    }
+
+    constexpr size_type length() const noexcept
+    {
+        return size();
+    }
+
+    constexpr bool empty() const noexcept
+    {
+        return data_[0] == value_type{};
+    }
+
+    static constexpr size_type max_size() noexcept
+    {
+        return N;
+    }
+
+    static constexpr size_type capacity() noexcept
+    {
+        return N;
+    }
+
+    // Element access.
+    constexpr reference operator[](size_type pos) noexcept
+    {
+        return data_[pos];
+    }
+
+    constexpr const_reference operator[](size_type pos) const noexcept
+    {
+        return data_[pos];
+    }
+
+    constexpr reference at(size_type pos)
+    {
+        if (pos >= size())
+        {
+            throw std::out_of_range("static_cstring::at");
+        }
+        return data_[pos];
+    }
+
+    constexpr const_reference at(size_type pos) const
+    {
+        if (pos >= size())
+        {
+            throw std::out_of_range("static_cstring::at");
+        }
+        return data_[pos];
+    }
+
+    constexpr reference front() noexcept
+    {
+        BOOST_STATIC_STRING_ASSERT(!empty());
+        return data_[0];
+    }
+
+    constexpr const_reference front() const noexcept
+    {
+        BOOST_STATIC_STRING_ASSERT(!empty());
+        return data_[0];
+    }
+
+    constexpr reference back() noexcept
+    {
+        BOOST_STATIC_STRING_ASSERT(!empty());
+        return data_[size() - 1];
+    }
+
+    constexpr const_reference back() const noexcept
+    {
+        BOOST_STATIC_STRING_ASSERT(!empty());
+        return data_[size() - 1];
+    }
+
+    constexpr pointer data() noexcept
+    {
+        return data_;
+    }
+
+    constexpr const_pointer data() const noexcept
+    {
+        return data_;
+    }
+
+    constexpr const_pointer c_str() const noexcept
+    {
+        return data_;
+    }
+
+    // Iterators.
+    constexpr iterator begin() noexcept
+    {
+        return data_;
+    }
+
+    constexpr const_iterator begin() const noexcept
+    {
+        return data_;
+    }
+
+    constexpr const_iterator cbegin() const noexcept
+    {
+        return data_;
+    }
+
+    constexpr iterator end() noexcept
+    {
+        return data_ + size();
+    }
+
+    constexpr const_iterator end() const noexcept
+    {
+        return data_ + size();
+    }
+
+    constexpr const_iterator cend() const noexcept
+    {
+        return data_ + size();
+    }
+
+    // Modifiers.
+    constexpr void clear() noexcept
+    {
+        set_size(0);
+    }
+
+    constexpr basic_static_cstring& assign(const CharT* s)
+    {
+        return assign(s, traits_type::length(s));
+    }
+
+    constexpr basic_static_cstring& assign(const CharT* s, size_type count)
+    {
+        if (count > N)
+        {
+            throw std::length_error("static_cstring::assign");
+        }
+        traits_type::copy(data_, s, count);
+        set_size(count);
+        return *this;
+    }
+
+    constexpr basic_static_cstring& assign(size_type count, CharT ch)
+    {
+        if (count > N)
+        {
+            throw std::length_error("static_cstring::assign");
+        }
+        traits_type::assign(data_, count, ch);
+        set_size(count);
+        return *this;
+    }
+
+    constexpr basic_static_cstring& operator=(const CharT* s)
+    {
+        return assign(s);
+    }
+
+    constexpr void push_back(CharT ch)
+    {
+        const size_type sz = size();
+        if (sz >= N)
+        {
+            throw std::length_error("static_cstring::push_back");
+        }
+        data_[sz] = ch;
+        set_size(sz + 1);
+    }
+
+    constexpr void pop_back() noexcept
+    {
+        BOOST_STATIC_STRING_ASSERT(!empty());
+        set_size(size() - 1);
+    }
+
+    constexpr basic_static_cstring& append(const CharT* s)
+    {
+        return append(s, traits_type::length(s));
+    }
+
+    constexpr basic_static_cstring& append(const CharT* s, size_type count)
+    {
+        const size_type sz = size();
+        if (sz + count > N)
+        {
+            throw std::length_error("static_cstring::append");
+        }
+        traits_type::copy(data_ + sz, s, count);
+        set_size(sz + count);
+        return *this;
+    }
+
+    constexpr basic_static_cstring& append(size_type count, CharT ch)
+    {
+        const size_type sz = size();
+        if (sz + count > N)
+        {
+            throw std::length_error("static_cstring::append");
+        }
+        traits_type::assign(data_ + sz, count, ch);
+        set_size(sz + count);
+        return *this;
+    }
+
+    constexpr basic_static_cstring& operator+=(const CharT* s)
+    {
+        return append(s);
+    }
+
+    constexpr basic_static_cstring& operator+=(CharT ch)
+    {
+        push_back(ch);
+        return *this;
+    }
+
+    // Comparisons.
+    constexpr int compare(const basic_static_cstring& other) const noexcept
+    {
+        const size_type lhs_sz = size();
+        const size_type rhs_sz = other.size();
+        const int result = traits_type::compare(data_, other.data_, (std::min)(lhs_sz, rhs_sz));
+
+        return result != 0
+                 ? result
+                 : lhs_sz < rhs_sz
+                 ? -1
+                 : lhs_sz > rhs_sz
+                 ? 1
+                 : 0;
+    }
+
+    constexpr int compare(const CharT* s) const noexcept
+    {
+        return compare(basic_static_cstring(s));
+    }
+
+    // Conversions.
+    constexpr operator std::basic_string_view<CharT, Traits>() const noexcept
+    {
+        return {data_, size()};
+    }
+
+    std::basic_string<CharT, Traits> str() const
+    {
+        return {data_, size()};
+    }
+
+    // Swap.
+    constexpr void swap(basic_static_cstring& other) noexcept
+    {
+        basic_static_cstring tmp = *this;
+        *this = other;
+        other = tmp;
+    }
+
+    // Defaulted comparisons for structural type (C++20).
+    constexpr bool operator==(const basic_static_cstring&) const noexcept = default;
+    constexpr auto operator<=>(const basic_static_cstring&) const noexcept = default;
+};
+
+#if defined(BOOST_STATIC_STRING_USE_DEDUCT)
+
+// Deduction guide.
+template<std::size_t N, typename CharT>
+basic_static_cstring(const CharT(&)[N]) -> basic_static_cstring<N - 1, CharT>;
+
+#endif
+
+// Comparison with const CharT*.
+template<std::size_t N, typename CharT, typename Traits>
+constexpr bool operator==(const basic_static_cstring<N, CharT, Traits>& lhs,
+                          const CharT* rhs) noexcept
+{
+    return lhs.compare(rhs) == 0;
+}
+
+template<std::size_t N, typename CharT, typename Traits>
+constexpr bool operator==(const CharT* lhs,
+                          const basic_static_cstring<N, CharT, Traits>& rhs) noexcept
+{
+    return rhs.compare(lhs) == 0;
+}
+
+// Stream output.
+template<std::size_t N, typename CharT, typename Traits>
+std::basic_ostream<CharT, Traits>& operator<<(std::basic_ostream<CharT, Traits>& os,
+                                              const basic_static_cstring<N, CharT, Traits>& str)
+{
+    return os << str.c_str();
+}
+
+// Alias templates.
+template<std::size_t N>
+using static_cstring = basic_static_cstring<N, char>;
+
+template<std::size_t N>
+using static_wcstring = basic_static_cstring<N, wchar_t>;
+
+}
+}
+
+#endif

example/static_cstring/static_cstring_test.cpp

@@ -0,0 +1,671 @@
+//
+// Copyright (c) 2025 Gennaro Prota (gennaro dot prota at gmail dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at https://www.boost.org/LICENSE_1_0.txt)
+//
+// Official repository: https://github.com/boostorg/static_string
+//
+
+#include "static_cstring.hpp"
+
+#include <boost/core/lightweight_test.hpp>
+#include <climits>
+#include <cstring>
+#include <sstream>
+#include <string>
+#include <string_view>
+#include <type_traits>
+
+namespace boost {
+namespace static_strings {
+
+static
+void
+testCStringSizeGuarantee()
+{
+    // Core guarantee: sizeof is exactly N + 1 (no size member).
+    static_assert(sizeof(static_cstring<0>) == 1, "");
+    static_assert(sizeof(static_cstring<1>) == 2, "");
+    static_assert(sizeof(static_cstring<10>) == 11, "");
+    static_assert(sizeof(static_cstring<63>) == 64, "");
+    static_assert(sizeof(static_cstring<64>) == 65, "");
+    static_assert(sizeof(static_cstring<127>) == 128, "");
+    static_assert(sizeof(static_cstring<UCHAR_MAX>) == (UCHAR_MAX + 1), "");
+    static_assert(sizeof(static_cstring<UCHAR_MAX + 1>) == (UCHAR_MAX + 2), "");
+    static_assert(sizeof(static_cstring<1000>) == 1001, "");
+}
+
+static
+void
+testCStringRemainingCapacityTrick()
+{
+    // Test the remaining-capacity optimization for N <= UCHAR_MAX.
+
+    // Full capacity: Last byte is both null terminator AND remaining == 0.
+    {
+        static_cstring<5> full("12345");
+        BOOST_TEST(full.size() == 5);
+        BOOST_TEST(full.capacity() == 5);
+        BOOST_TEST(full.data()[5] == '\0');
+        BOOST_TEST(std::strcmp(full.c_str(), "12345") == 0);
+    }
+
+    // Partial fill: Null terminator at position size, remaining at position N.
+    {
+        static_cstring<10> partial("Hi");
+        BOOST_TEST(partial.size() == 2);
+        BOOST_TEST(partial.capacity() == 10);
+        BOOST_TEST(partial.data()[2] == '\0');
+        BOOST_TEST(static_cast<unsigned char>(partial.data()[10]) == 8);
+    }
+
+    // Empty string.
+    {
+        static_cstring<10> empty;
+        BOOST_TEST(empty.size() == 0);
+        BOOST_TEST(empty.capacity() == 10);
+        BOOST_TEST(empty.data()[0] == '\0');
+        BOOST_TEST(static_cast<unsigned char>(empty.data()[10]) == 10);
+    }
+
+    // Edge case: N == UCHAR_MAX (max for our trick).
+    {
+        static_cstring<UCHAR_MAX> large;
+        large.assign(100, 'x');
+        BOOST_TEST(large.size() == 100);
+        BOOST_TEST(large.capacity() == UCHAR_MAX);
+        BOOST_TEST(static_cast<unsigned char>(large.data()[UCHAR_MAX]) == (UCHAR_MAX - large.size()));
+    }
+}
+
+template<typename S>
+struct CStringTypeTraits
+{
+    static_assert(std::is_trivially_copyable<S>::value);
+    static_assert(std::is_trivially_copy_constructible<S>::value);
+    static_assert(std::is_trivially_move_constructible<S>::value);
+    static_assert(std::is_trivially_copy_assignable<S>::value);
+    static_assert(std::is_trivially_move_assignable<S>::value);
+    static_assert(std::is_trivially_destructible<S>::value);
+};
+
+static
+void
+testCStringTypeTraits()
+{
+    {
+        using S = static_cstring<0>;
+        CStringTypeTraits< S > check;
+        static_cast<void>(check);
+    }
+    {
+        using S = static_cstring<63>;
+        CStringTypeTraits< S > check;
+        static_cast<void>(check);
+    }
+    {
+        using S = static_cstring<300>;
+        CStringTypeTraits< S > check;
+        static_cast<void>(check);
+    }
+}
+
+static
+void
+testCStringConstruct()
+{
+    // Default construction.
+    {
+        static_cstring<1> s;
+        BOOST_TEST(s.empty());
+        BOOST_TEST(s.size() == 0);
+        BOOST_TEST(s == "");
+        BOOST_TEST(*s.end() == 0);
+    }
+
+    // Construct with count and char.
+    {
+        static_cstring<4> s1(3, 'x');
+        BOOST_TEST(!s1.empty());
+        BOOST_TEST(s1.size() == 3);
+        BOOST_TEST(s1 == "xxx");
+        BOOST_TEST(*s1.end() == 0);
+        BOOST_TEST_THROWS(
+            (static_cstring<2>(3, 'x')),
+            std::length_error);
+    }
+
+    // Construct from a C string.
+    {
+        static_cstring<5> s1("12345");
+        BOOST_TEST(s1.size() == 5);
+        BOOST_TEST(s1 == "12345");
+        BOOST_TEST(*s1.end() == 0);
+        BOOST_TEST_THROWS(
+            (static_cstring<4>("12345")),
+            std::length_error);
+    }
+
+    // Construct from a C string with count.
+    {
+        static_cstring<5> s1("UVXYZ", 3);
+        BOOST_TEST(s1 == "UVX");
+        BOOST_TEST(*s1.end() == 0);
+    }
+
+    // Copy construction.
+    {
+        static_cstring<5> s1("12345");
+        static_cstring<5> s2(s1);
+        BOOST_TEST(s2 == "12345");
+        BOOST_TEST(*s2.end() == 0);
+    }
+}
+
+static
+void
+testCStringAssignment()
+{
+    // assign(size_type count, CharT ch).
+    BOOST_TEST(static_cstring<3>{}.assign(1, '*') == "*");
+    BOOST_TEST(static_cstring<3>{}.assign(3, '*') == "***");
+    BOOST_TEST(static_cstring<3>{"abc"}.assign(3, '*') == "***");
+    BOOST_TEST_THROWS(static_cstring<1>{"a"}.assign(2, '*'), std::length_error);
+
+    // assign(CharT const* s, size_type count).
+    BOOST_TEST(static_cstring<3>{}.assign("abc", 3) == "abc");
+    BOOST_TEST(static_cstring<3>{"*"}.assign("abc", 3) == "abc");
+    BOOST_TEST_THROWS(static_cstring<1>{}.assign("abc", 3), std::length_error);
+
+    // assign(CharT const* s).
+    BOOST_TEST(static_cstring<3>{}.assign("abc") == "abc");
+    BOOST_TEST(static_cstring<3>{"*"}.assign("abc") == "abc");
+    BOOST_TEST_THROWS(static_cstring<1>{}.assign("abc"), std::length_error);
+
+    // operator=(const CharT* s).
+    {
+        static_cstring<3> s1;
+        s1 = "123";
+        BOOST_TEST(s1 == "123");
+        BOOST_TEST(*s1.end() == 0);
+        static_cstring<1> s2;
+        BOOST_TEST_THROWS(
+            s2 = "123",
+            std::length_error);
+    }
+
+    // Copy assignment.
+    {
+        static_cstring<3> s1("123");
+        static_cstring<3> s2;
+        s2 = s1;
+        BOOST_TEST(s2 == "123");
+        BOOST_TEST(*s2.end() == 0);
+    }
+}
+
+static
+void
+testCStringElements()
+{
+    using ccs3 = static_cstring<3> const;
+
+    // at(size_type pos).
+    BOOST_TEST(static_cstring<3>{"abc"}.at(0) == 'a');
+    BOOST_TEST(static_cstring<3>{"abc"}.at(2) == 'c');
+    BOOST_TEST_THROWS(static_cstring<3>{""}.at(0), std::out_of_range);
+    BOOST_TEST_THROWS(static_cstring<3>{"abc"}.at(4), std::out_of_range);
+
+    // at(size_type pos) const.
+    BOOST_TEST(ccs3{"abc"}.at(0) == 'a');
+    BOOST_TEST(ccs3{"abc"}.at(2) == 'c');
+    BOOST_TEST_THROWS(ccs3{""}.at(0), std::out_of_range);
+
+    // operator[](size_type pos).
+    BOOST_TEST(static_cstring<3>{"abc"}[0] == 'a');
+    BOOST_TEST(static_cstring<3>{"abc"}[2] == 'c');
+    BOOST_TEST(static_cstring<3>{"abc"}[3] == 0);
+    BOOST_TEST(static_cstring<3>{""}[0] == 0);
+
+    // front() / back().
+    BOOST_TEST(static_cstring<3>{"abc"}.front() == 'a');
+    BOOST_TEST(static_cstring<3>{"abc"}.back() == 'c');
+
+    // data() / c_str().
+    {
+        static_cstring<3> s("123");
+        BOOST_TEST(std::memcmp(s.data(), "123", 3) == 0);
+        BOOST_TEST(std::memcmp(s.c_str(), "123\0", 4) == 0);
+    }
+
+    // Modification through element access.
+    {
+        static_cstring<5> s("12345");
+        s[1] = '_';
+        BOOST_TEST(s == "1_345");
+        s.front() = 'A';
+        BOOST_TEST(s == "A_345");
+        s.back() = 'Z';
+        BOOST_TEST(s == "A_34Z");
+    }
+}
+
+static
+void
+testCStringIterators()
+{
+    {
+        static_cstring<3> s;
+        BOOST_TEST(std::distance(s.begin(), s.end()) == 0);
+        s = "123";
+        BOOST_TEST(std::distance(s.begin(), s.end()) == 3);
+    }
+    {
+        static_cstring<3> const s("123");
+        BOOST_TEST(std::distance(s.begin(), s.end()) == 3);
+        BOOST_TEST(std::distance(s.cbegin(), s.cend()) == 3);
+    }
+
+    // Iteration.
+    {
+        static_cstring<5> s("hello");
+        std::string result;
+        for (const char c : s)
+        {
+            result += c;
+        }
+        BOOST_TEST(result == "hello");
+    }
+}
+
+static
+void
+testCStringCapacity()
+{
+    // empty().
+    BOOST_TEST(static_cstring<0>{}.empty());
+    BOOST_TEST(static_cstring<1>{}.empty());
+    BOOST_TEST(!static_cstring<1>{"a"}.empty());
+
+    // size().
+    BOOST_TEST(static_cstring<0>{}.size() == 0);
+    BOOST_TEST(static_cstring<1>{"a"}.size() == 1);
+    BOOST_TEST(static_cstring<5>{"abc"}.size() == 3);
+
+    // length().
+    BOOST_TEST(static_cstring<0>{}.length() == 0);
+    BOOST_TEST(static_cstring<3>{"abc"}.length() == 3);
+
+    // max_size().
+    BOOST_TEST(static_cstring<0>{}.max_size() == 0);
+    BOOST_TEST(static_cstring<5>{"abc"}.max_size() == 5);
+
+    // capacity().
+    BOOST_TEST(static_cstring<0>{}.capacity() == 0);
+    BOOST_TEST(static_cstring<5>{"abc"}.capacity() == 5);
+}
+
+static
+void
+testCStringClear()
+{
+    static_cstring<3> s("123");
+    BOOST_TEST(!s.empty());
+    s.clear();
+    BOOST_TEST(s.empty());
+    BOOST_TEST(s.size() == 0);
+    BOOST_TEST(*s.end() == 0);
+    BOOST_TEST(s == "");
+}
+
+static
+void
+testCStringPushPop()
+{
+    // push_back().
+    {
+        static_cstring<5> s("abc");
+        s.push_back('d');
+        BOOST_TEST(s == "abcd");
+        BOOST_TEST(s.size() == 4);
+        BOOST_TEST(*s.end() == 0);
+
+        s.push_back('e');
+        BOOST_TEST(s == "abcde");
+        BOOST_TEST(s.size() == 5);
+
+        BOOST_TEST_THROWS(s.push_back('f'), std::length_error);
+    }
+
+    // pop_back().
+    {
+        static_cstring<5> s("abcde");
+        s.pop_back();
+        BOOST_TEST(s == "abcd");
+        BOOST_TEST(s.size() == 4);
+        BOOST_TEST(*s.end() == 0);
+
+        s.pop_back();
+        s.pop_back();
+        s.pop_back();
+        s.pop_back();
+        BOOST_TEST(s.empty());
+    }
+}
+
+static
+void
+testCStringAppend()
+{
+    // append(const CharT* s).
+    {
+        static_cstring<12> s("Hello");
+        s.append(", World");
+        BOOST_TEST(s == "Hello, World");
+        BOOST_TEST(*s.end() == 0);
+    }
+    {
+        static_cstring<5> s("abc");
+        BOOST_TEST_THROWS(s.append("def"), std::length_error);
+    }
+
+    // append(const CharT* s, size_type count)
+    {
+        static_cstring<10> s("abc");
+        s.append("defgh", 3);
+        BOOST_TEST(s == "abcdef");
+        BOOST_TEST(*s.end() == 0);
+    }
+
+    // append(size_type count, CharT ch)
+    {
+        static_cstring<10> s("abc");
+        s.append(3, 'x');
+        BOOST_TEST(s == "abcxxx");
+        BOOST_TEST(*s.end() == 0);
+        BOOST_TEST_THROWS(s.append(5, 'y'), std::length_error);
+    }
+
+    // operator+=()
+    {
+        static_cstring<10> s("abc");
+        s += "def";
+        BOOST_TEST(s == "abcdef");
+        s += 'g';
+        BOOST_TEST(s == "abcdefg");
+        BOOST_TEST(*s.end() == 0);
+    }
+}
+
+static
+void
+testCStringComparison()
+{
+    // operator==() / operator!=().
+    {
+        static_cstring<10> a("abc");
+        static_cstring<10> b("abc");
+        static_cstring<10> c("abd");
+
+        BOOST_TEST(a == b);
+        BOOST_TEST(!(a == c));
+        BOOST_TEST(a != c);
+        BOOST_TEST(!(a != b));
+    }
+
+    // operator<(), <=(), >(), >=().
+    {
+        static_cstring<10> a("abc");
+        static_cstring<10> b("abd");
+
+        BOOST_TEST(a < b);
+        BOOST_TEST(a <= b);
+        BOOST_TEST(a <= a);
+        BOOST_TEST(b > a);
+        BOOST_TEST(b >= a);
+        BOOST_TEST(b >= b);
+    }
+
+    // Comparison with CharT const*.
+    {
+        static_cstring<10> s("hello");
+        BOOST_TEST(s == "hello");
+        BOOST_TEST("hello" == s);
+        BOOST_TEST(s != "world");
+        BOOST_TEST("world" != s);
+    }
+
+    // compare().
+    {
+        static_cstring<10> s("abc");
+        BOOST_TEST(s.compare("abc") == 0);
+        BOOST_TEST(s.compare("abd") < 0);
+        BOOST_TEST(s.compare("abb") > 0);
+    }
+}
+
+static
+void
+testCStringConversion()
+{
+    // operator string_view().
+    {
+        static_cstring<10> s("hello");
+        std::string_view sv = s;
+        BOOST_TEST(sv == "hello");
+        BOOST_TEST(sv.size() == 5);
+    }
+
+    // str().
+    {
+        static_cstring<10> s("hello");
+        std::string str = s.str();
+        BOOST_TEST(str == "hello");
+        BOOST_TEST(str.size() == 5);
+    }
+}
+
+static
+void
+testCStringStream()
+{
+    static_cstring<10> s("hello");
+    std::ostringstream oss;
+    oss << s;
+    BOOST_TEST(oss.str() == "hello");
+}
+
+static
+void
+testCStringSwap()
+{
+    static_cstring<10> a("hello");
+    static_cstring<10> b("world");
+
+    a.swap(b);
+
+    BOOST_TEST(a == "world");
+    BOOST_TEST(b == "hello");
+}
+
+static
+void
+testCStringConstexpr()
+{
+    // constexpr construction and operations.
+    constexpr static_cstring<10> ce("test");
+    static_assert(ce.size() == 4, "");
+    static_assert(ce[0] == 't', "");
+    static_assert(ce[1] == 'e', "");
+    static_assert(ce[2] == 's', "");
+    static_assert(ce[3] == 't', "");
+    static_assert(!ce.empty(), "");
+    static_assert(ce.max_size() == 10, "");
+    static_assert(ce.capacity() == 10, "");
+
+    constexpr static_cstring<5> ce_empty;
+    static_assert(ce_empty.empty(), "");
+    static_assert(ce_empty.size() == 0, "");
+}
+
+// Helper struct to test NTTP.
+template<basic_static_cstring S>
+struct NTTPHelper
+{
+    static constexpr std::size_t size() noexcept
+    {
+        return S.size();
+    }
+
+    static constexpr const char* c_str() noexcept
+    {
+        return S.c_str();
+    }
+};
+
+static
+void
+testCStringNTTP()
+{
+    // Test non-type template parameter usage (C++20).
+
+    // Test size deduction from string literals.
+    BOOST_TEST(NTTPHelper<"hello">::size() == 5);
+    BOOST_TEST(NTTPHelper<"">::size() == 0);
+    BOOST_TEST(NTTPHelper<"test">::size() == 4);
+
+    // Test that different strings create different types
+    constexpr bool same_type = std::is_same_v<
+        NTTPHelper<"hello">,
+        NTTPHelper<"hello">>;
+    BOOST_TEST(same_type);
+
+    constexpr bool different_type = !std::is_same_v<
+        NTTPHelper<"hello">,
+        NTTPHelper<"world">>;
+    BOOST_TEST(different_type);
+
+    // Test constexpr access.
+    constexpr std::size_t len = NTTPHelper<"constexpr">::size();
+    static_assert(len == 9, "");
+}
+
+static
+void
+testCStringPODUsage()
+{
+    // Test usage in POD types (the original motivation).
+    struct UserRecord
+    {
+        int id;
+        static_cstring<63> name;
+        unsigned int flags;
+    };
+
+    static_assert(sizeof(static_cstring<63>) == 64, "");
+    static_assert(std::is_trivially_copyable<UserRecord>::value, "");
+
+    UserRecord user{};
+    user.id = 42;
+    user.name = "Alice";
+    user.flags = 0xFF;
+
+    BOOST_TEST(user.id == 42);
+    BOOST_TEST(user.name.size() == 5);
+    BOOST_TEST(user.name == "Alice");
+    BOOST_TEST(user.flags == 0xFF);
+
+    // Copy the struct.
+    UserRecord copy = user;
+    BOOST_TEST(copy.name == "Alice");
+
+    // memcpy() should work.
+    UserRecord memcpy_dest;
+    std::memcpy(&memcpy_dest, &user, sizeof(UserRecord));
+    BOOST_TEST(memcpy_dest.name == "Alice");
+}
+
+static
+void
+testCStringLargeCapacity()
+{
+    // Test strings with N > UCHAR_MAX (no remaining-capacity trick).
+    {
+        static_cstring<300> s;
+        BOOST_TEST(s.empty());
+        BOOST_TEST(s.size() == 0);
+
+        s = "This is a test string";
+        BOOST_TEST(s.size() == 21);
+        BOOST_TEST(s == "This is a test string");
+
+        s.clear();
+        BOOST_TEST(s.empty());
+    }
+
+    // Large string operations.
+    {
+        static_cstring<500> s;
+        s.assign(400, 'x');
+        BOOST_TEST(s.size() == 400);
+        BOOST_TEST(s[0] == 'x');
+        BOOST_TEST(s[399] == 'x');
+        BOOST_TEST(*s.end() == 0);
+    }
+}
+
+static
+void
+testCStringWideChar()
+{
+    // Test with wchar_t.
+    {
+        static_wcstring<10> ws;
+        BOOST_TEST(ws.empty());
+        BOOST_TEST(ws.size() == 0);
+    }
+
+    {
+        static_wcstring<10> ws(L"hello");
+        BOOST_TEST(ws.size() == 5);
+        BOOST_TEST(ws[0] == L'h');
+        BOOST_TEST(ws[4] == L'o');
+        BOOST_TEST(*ws.end() == 0);
+    }
+}
+
+int
+runTests()
+{
+  testCStringSizeGuarantee();
+  testCStringRemainingCapacityTrick();
+  testCStringTypeTraits();
+  testCStringConstruct();
+  testCStringAssignment();
+  testCStringElements();
+  testCStringIterators();
+  testCStringCapacity();
+  testCStringClear();
+  testCStringPushPop();
+  testCStringAppend();
+  testCStringComparison();
+  testCStringConversion();
+  testCStringStream();
+  testCStringSwap();
+  testCStringConstexpr();
+  testCStringNTTP();
+  testCStringPODUsage();
+  testCStringLargeCapacity();
+  testCStringWideChar();
+
+  return report_errors();
+}
+}
+}
+
+int
+main()
+{
+  return boost::static_strings::runTests();
+}

include/boost/static_string/config.hpp

@@ -14,6 +14,17 @@
 // Are we dependent on Boost?
 // #define BOOST_STATIC_STRING_STANDALONE
 
+#include <cstdint>
+
+// detect 32/64 bit
+#if UINTPTR_MAX == UINT64_MAX
+#define BOOST_STATIC_STRING_ARCH 64
+#elif UINTPTR_MAX == UINT32_MAX
+#define BOOST_STATIC_STRING_ARCH 32
+#else
+#error Unknown or unsupported architecture, please open an issue
+#endif
+
 // Can we have deduction guides?
 #if __cpp_deduction_guides >= 201703L
 #define BOOST_STATIC_STRING_USE_DEDUCT
@@ -128,9 +139,6 @@
 #ifndef BOOST_STATIC_STRING_THROW
 #define BOOST_STATIC_STRING_THROW(ex) BOOST_THROW_EXCEPTION(ex)
 #endif
-#ifndef BOOST_STATIC_STRING_STATIC_ASSERT
-#define BOOST_STATIC_STRING_STATIC_ASSERT(cond, msg) BOOST_STATIC_ASSERT_MSG(cond, msg)
-#endif
 #ifndef BOOST_STATIC_STRING_ASSERT
 #define BOOST_STATIC_STRING_ASSERT(cond) BOOST_ASSERT(cond)
 #endif
@@ -138,9 +146,6 @@
 #ifndef BOOST_STATIC_STRING_THROW
 #define BOOST_STATIC_STRING_THROW(ex) throw ex
 #endif
-#ifndef BOOST_STATIC_STRING_STATIC_ASSERT
-#define BOOST_STATIC_STRING_STATIC_ASSERT(cond, msg) static_assert(cond, msg)
-#endif
 #ifndef BOOST_STATIC_STRING_ASSERT
 #define BOOST_STATIC_STRING_ASSERT(cond) assert(cond)
 #endif
@@ -150,7 +155,6 @@
 #include <boost/config.hpp>
 #include <boost/assert.hpp>
 #include <boost/container_hash/hash.hpp>
-#include <boost/static_assert.hpp>
 #include <boost/utility/string_view.hpp>
 #include <boost/core/detail/string_view.hpp>
 #include <boost/throw_exception.hpp>
@@ -164,27 +168,31 @@
 #include <cassert>
 #include <stdexcept>
 
+#if defined(__has_include)
+#  if !__has_include(<string_view>)
+#    define BOOST_STATIC_STRING_NO_CXX17_HDR_STRING_VIEW
+#  endif
 /*
  * Replicate the logic from Boost.Config
  */
 // GNU libstdc++3:
-#if defined(__GLIBCPP__) || defined(__GLIBCXX__)
-#if (BOOST_LIBSTDCXX_VERSION < 70100) || (__cplusplus <= 201402L)
-#  define BOOST_STATIC_STRING_NO_CXX17_HDR_STRING_VIEW
-#endif
+#elif defined(__GLIBCPP__) || defined(__GLIBCXX__)
+#  if ((__GNUC__ * 10000 + __GNUC_MINOR__ * 100 + __GNUC_PATCHLEVEL__) < 70100) || (__cplusplus <= 201402L)
+#    define BOOST_STATIC_STRING_NO_CXX17_HDR_STRING_VIEW
+#  endif
 // libc++:
 #elif defined(_LIBCPP_VERSION)
-#if (_LIBCPP_VERSION < 4000) || (__cplusplus <= 201402L)
-#  define BOOST_STATIC_STRING_NO_CXX17_HDR_STRING_VIEW
-#endif
+#  if (_LIBCPP_VERSION < 4000) || (__cplusplus <= 201402L)
+#    define BOOST_STATIC_STRING_NO_CXX17_HDR_STRING_VIEW
+#  endif
 // MSVC uses logic from catch all for BOOST_NO_CXX17_HDR_STRING_VIEW
 // catch all:
 #elif !defined(_YVALS) && !defined(_CPPLIB_VER)
-#if (!defined(__has_include) || (__cplusplus < 201700))
-#  define BOOST_STATIC_STRING_NO_CXX17_HDR_STRING_VIEW
-#elif !__has_include(<string_view>)
-#  define BOOST_STATIC_STRING_NO_CXX17_HDR_STRING_VIEW
-#endif
+#  if (!defined(__has_include) || (__cplusplus < 201700))
+#    define BOOST_STATIC_STRING_NO_CXX17_HDR_STRING_VIEW
+#  elif !__has_include(<string_view>)
+#    define BOOST_STATIC_STRING_NO_CXX17_HDR_STRING_VIEW
+#  endif
 #endif
 
 #if !defined(BOOST_STATIC_STRING_NO_CXX17_HDR_STRING_VIEW) || \
@@ -228,6 +236,24 @@ defined(BOOST_STATIC_STRING_CPP14)
 #define BOOST_STATIC_STRING_GCC5_BAD_CONSTEXPR
 #endif
 
+#ifndef BOOST_STATIC_STRING_STANDALONE
+#if ! defined(BOOST_NO_CWCHAR) && ! defined(BOOST_NO_SWPRINTF)
+#define BOOST_STATIC_STRING_HAS_WCHAR
+#endif
+#else
+#ifndef __has_include
+// If we don't have __has_include in standalone,
+// we will assume that <cwchar> exists.
+#define BOOST_STATIC_STRING_HAS_WCHAR
+#elif __has_include(<cwchar>)
+#define BOOST_STATIC_STRING_HAS_WCHAR
+#endif
+#endif
+
+#ifdef BOOST_STATIC_STRING_HAS_WCHAR
+#include <cwchar>
+#endif
+
 // Define the basic string_view type used by the library
 // Conversions to and from other available string_view types
 // are still defined.
@@ -249,4 +275,25 @@ using basic_string_view =
 } // boost
 #endif
 
-#endif
+#if defined(__cpp_lib_to_string) && __cpp_lib_to_string >= 202306L // std::to_[w]string() redefined in terms of std::format()
+#define BOOST_STATIC_STRING_USE_STD_FORMAT
+#endif
+
+#if defined(__GNUC__) && (__GNUC__ >= 5) && (__GNUC__ <= 10) && !defined(__clang__)
+// Workaround for GCC complaining about nested classes being private.
+#define BOOST_STATIC_STRING_GCC_NESTED_CLASS_WORKAROUND public:
+#else
+#define BOOST_STATIC_STRING_GCC_NESTED_CLASS_WORKAROUND
+#endif
+
+// GCC 9 incorrectly rejects the pointer equality comparison in
+// ptr_in_range() in constant expressions. GCC 10 and later handle
+// it correctly.
+//
+// Clang 3.7 and 9-19 have the same issue.
+#if (defined(__GNUC__) && !defined(__clang__) && (__GNUC__ == 9)) \
+    || (defined(__clang__) && ((__clang_major__ == 3 && __clang_minor__ == 7) || ((__clang_major__ >= 9) && (__clang_major__ <= 19))))
+#define BOOST_STATIC_STRING_CONSTEXPR_PTR_CMP_BROKEN
+#endif
+
+#endif

meta/libraries.json

@@ -7,12 +7,13 @@
     ],
     "description": "A fixed capacity dynamically sized string.",
     "category": [
-        "Container",
+        "Containers",
         "String"
     ],
     "maintainers": [
         "Alan de Freitas <alandefreitas@gmail.com>",
-        "Vinnie Falco <vinnie.falco@gmail.com>"
+        "Vinnie Falco <vinnie.falco@gmail.com>",
+        "Gennaro Prota <gennaro.prota@gmail.com>"
     ],
     "cxxstd": "11"
 }

test/CMakeLists.txt

@@ -7,6 +7,12 @@
 # Official repository: https://github.com/boostorg/static_string
 #
 
+# Custom target used by the boost super-project
+if(NOT TARGET tests)
+        add_custom_target(tests)
+        set_property(TARGET tests PROPERTY FOLDER _deps)
+endif()
+
 set(BOOST_STATIC_STRING_TESTS_FILES
         CMakeLists.txt
         Jamfile
@@ -23,3 +29,4 @@ add_executable(boost_static_string_tests ${BOOST_STATIC_STRING_TESTS_FILES})
 # See: BOOST_STATIC_STRING_UNIT_TEST_LIBRARIES
 target_link_libraries(boost_static_string_tests PRIVATE Boost::static_string)
 add_test(NAME boost_static_string_tests COMMAND boost_static_string_tests)
+add_dependencies(tests boost_static_string_tests)

test/Jamfile

@@ -8,18 +8,21 @@
 #
 
 import testing ;
-import ../../config/checks/config : requires ;
+import-search /boost/config/checks ;
+import config : requires ;
 
 local defines =
     [ requires
     cxx11_constexpr
     cxx11_decltype
     cxx11_hdr_tuple
+    cxx11_hdr_type_traits
     cxx11_template_aliases
     cxx11_variadic_templates
     ]
     ;
 
-project : requirements $(defines) ;
+project : requirements $(defines)
+    <library>/boost/static_string//boost_static_string ;
 
 run static_string.cpp ;

test/cmake_test/CMakeLists.txt

@@ -0,0 +1,24 @@
+# Copyright 2021-2025 Alexander Grund
+# Distributed under the Boost Software License, Version 1.0.
+# See accompanying file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt
+
+cmake_minimum_required(VERSION 3.8...3.16)
+
+project(cmake_subdir_test LANGUAGES CXX)
+
+# Those 2 should work the same
+# while using find_package for the installed Boost avoids the need to manually specify dependencies
+if(BOOST_CI_INSTALL_TEST)
+    find_package(boost_static_string REQUIRED)
+else()
+    set(BOOST_INCLUDE_LIBRARIES static_string)
+    add_subdirectory(../../../.. deps/boost EXCLUDE_FROM_ALL)
+endif()
+
+add_executable(main main.cpp)
+target_link_libraries(main Boost::static_string)
+
+enable_testing()
+add_test(NAME main COMMAND main)
+
+add_custom_target(check COMMAND ${CMAKE_CTEST_COMMAND} --output-on-failure -C $<CONFIG>)

test/cmake_test/main.cpp

@@ -0,0 +1,18 @@
+//
+// Copyright (c) 2025 Alexander Grund
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+// Official repository: https://github.com/boostorg/static_string
+//
+
+#include <boost/static_string.hpp>
+
+int main()
+{
+    // Smoke test only
+    boost::static_string<1> s_empty;
+    boost::static_string<4> s_3(3, 'x');
+    return (s_empty.empty() && s_3.size() == 3) ? 0 : 1;
+}

test/compile_fail.hpp

@@ -4,16 +4,6 @@
 namespace boost {
 namespace static_strings {
 
-static_assert(std::is_base_of<
-  detail::static_string_base<0, char, std::char_traits<char>>,
-              static_string<0>>::value,
-              "the zero size optimization shall be used for N = 0");
-
-static_assert(std::is_base_of<
-  detail::static_string_base<(std::numeric_limits<char>::max)() + 1, char, std::char_traits<char>>,
-              static_string<(std::numeric_limits<char>::max)() + 1>>::value,
-              "the minimum size type optimization shall be used for N > 0");
-
 static_assert(!detail::is_input_iterator<int>::value, "is_input_iterator is incorrect");
 static_assert(!detail::is_input_iterator<double>::value, "is_input_iterator is incorrect");
 static_assert(detail::is_input_iterator<int*>::value, "is_input_iterator is incorrect");

test/constexpr_tests.hpp

@@ -22,38 +22,77 @@ struct cxper_char_traits
   using int_type = int;
   using state_type = std::mbstate_t;
 
-  static constexpr void assign(char_type& a, const char_type& b) noexcept { a = b;  }
-  static constexpr bool eq(char_type a, char_type b) noexcept { return a == b; }
-  static constexpr bool lt(char_type a, char_type b) noexcept { return a < b; }
+  static constexpr void assign(char_type& a, const char_type& b) noexcept
+  {
+    a = b;
+  }
+
+  static constexpr bool eq(char_type a, char_type b) noexcept
+  {
+    return a == b;
+  }
+
+  static constexpr bool lt(char_type a, char_type b) noexcept
+  {
+    return a < b;
+  }
+
+  static constexpr int compare(const char_type* a, const char_type* b, std::size_t n)
+  {
+    for (; n--; ++a, ++b)
+    {
+      if(lt(*a, *b))
+        return 1;
+      else if(lt(*b, *a))
+        return -1;
+    }
+    return 0;
+  }
 
-  static constexpr int compare(const char_type*, const char_type*, std::size_t) { return 0; }
   static constexpr std::size_t length(const char_type* s)
   {
-    std::size_t n = 0;
-    while (*(s++));
-    return n;
+    auto ptr = s;
+    while (!eq(*ptr, char_type()))
+      ++ptr;
+    return ptr - s;
   }
-  static constexpr const char_type* find(const char_type*, std::size_t, const char_type&){ return 0; }
+
+  static constexpr const char_type* find(const char_type* s, std::size_t n, const char_type& ch)
+  {
+    for (; n--; ++s)
+    {
+      if (eq(*s, ch))
+        return s;
+    }
+    return nullptr;
+  }
+
   static constexpr char_type* move(char_type* dest, const char_type* src, std::size_t n)
   {
-    const auto temp = dest;
-    while (n--)
-      *(dest++) = *(src++);
-    return temp;
+    // This implementation does not handle overlapping ranges where
+    // dest > src. A correct implementation would need to detect this
+    // case and copy backwards, but detecting overlap requires pointer
+    // comparisons that many of the tested compiles (incorrectly) refuse
+    // in constant expressions.
+    //
+    // Since cxper_char_traits is only used for testing constexpr
+    // functionality and the tests do not exercise overlapping moves
+    // where dest > src, this simple forward copy is sufficient.
+    return copy(dest, src, n);
   }
+
   static constexpr char_type* copy(char_type* dest, const char_type* src, std::size_t n)
   {
-    const auto temp = dest;
-    while (n--)
-      *(dest++) = *(src++);
-    return temp;
+    for (auto ptr = dest; n--;)
+      assign(*ptr++, *src++);
+    return dest;
   }
+
   static constexpr char_type* assign(char_type* dest, std::size_t n, char_type ch)
   {
-    const auto temp = dest;
-    while (n--)
-      *(dest++) = ch;
-    return temp;
+    for (auto ptr = dest; n--;)
+      assign(*ptr++, ch);
+    return dest;
   }
 };
 #else
@@ -67,6 +106,23 @@ bool
 testConstantEvaluation()
 {
 #ifdef BOOST_STATIC_STRING_CPP20
+
+  // Check construction in a constexpr context
+  constexpr basic_static_string s("hello");
+  static_assert(s.size() == 5);
+  static_assert(s.static_capacity == 5);
+  static_assert(s == "hello");
+
+  // Check assignment in a constexpr context
+  constexpr auto s2 =
+  []()
+  {
+    basic_static_string s("hello");
+    s = "world";
+    return s;
+  }();
+  static_assert(s2 == "world");
+
   // c++20 constexpr tests
   cstatic_string a;
   cstatic_string b(1, 'a');
@@ -171,8 +227,10 @@ testConstantEvaluation()
 
   a.substr(0);
 
+#ifdef BOOST_STATIC_STRING_HAS_ANY_STRING_VIEW
   // subview
   a.subview(0);
+#endif
 
   // copy
   char k[20]{};
@@ -198,7 +256,8 @@ testConstantEvaluation()
   a.replace(a.begin(), a.end(), a.begin(), a.end());
   a.replace(a.begin(), a.end(), {'a'});
 
-#ifdef BOOST_STATIC_STRING_IS_CONST_EVAL
+#if defined(BOOST_STATIC_STRING_IS_CONST_EVAL) \
+        && !defined(BOOST_STATIC_STRING_CONSTEXPR_PTR_CMP_BROKEN)
   a.clear();
   a.replace(a.begin(), a.end(), "a");
   a.replace(a.begin(), a.end(), "a", 1);
@@ -386,7 +445,8 @@ testConstantEvaluation()
   a.replace(a.begin(), a.end(), a.begin(), a.end());
   a.replace(a.begin(), a.end(), {'a'});
 
-#ifdef BOOST_STATIC_STRING_IS_CONST_EVAL
+#if defined(BOOST_STATIC_STRING_IS_CONST_EVAL) \
+        && !defined(BOOST_STATIC_STRING_CONSTEXPR_PTR_CMP_BROKEN)
   a.clear();
   a.replace(a.begin(), a.end(), "a");
   a.replace(a.begin(), a.end(), "a", 1);
@@ -558,7 +618,8 @@ testConstantEvaluation()
   a.replace(a.begin(), a.end(), a.begin(), a.end());
   a.replace(a.begin(), a.end(), {'a'});
 
-#ifdef BOOST_STATIC_STRING_IS_CONST_EVAL
+#if defined(BOOST_STATIC_STRING_IS_CONST_EVAL) \
+        && !defined(BOOST_STATIC_STRING_CONSTEXPR_PTR_CMP_BROKEN)
   a.clear();
   a.replace(a.begin(), a.end(), "a");
   a.replace(a.begin(), a.end(), "a", 1);
@@ -605,5 +666,28 @@ testConstantEvaluation()
     cstatic_string().empty();
 #endif
 }
+
+#if __cpp_nontype_template_args >= 201911L
+
+template<basic_static_string<32, char, cxper_char_traits> X>
+struct nttp_primary
+{
+  static constexpr bool value = false;
+};
+
+template<>
+struct nttp_primary<"test string">
+{
+  static constexpr bool value = true;
+};
+
+static_assert(!nttp_primary<"random string">::value,
+  "structural equality broken");
+
+static_assert(nttp_primary<"test string">::value,
+  "structural equality broken");
+
+#endif
+
 } // static_strings
-} // boost
+} // boost