diff --git a/include/boost/thread/detail/string_to_unsigned.hpp b/include/boost/thread/detail/string_to_unsigned.hpp
new file mode 100644
index 00000000..9e58aabb
--- /dev/null
+++ b/include/boost/thread/detail/string_to_unsigned.hpp
@@ -0,0 +1,55 @@
+#ifndef BOOST_THREAD_DETAIL_STRING_TO_UNSIGNED_HPP_INCLUDED
+#define BOOST_THREAD_DETAIL_STRING_TO_UNSIGNED_HPP_INCLUDED
+
+// Copyright 2023 Peter Dimov
+// Distributed under the Boost Software License, Version 1.0.
+// https://www.boost.org/LICENSE_1_0.txt
+
+#include <string>
+#include <climits>
+
+namespace boost
+{
+namespace thread_detail
+{
+
+inline bool string_to_unsigned( std::string const& s, unsigned& v )
+{
+    v = 0;
+
+    if( s.empty() )
+    {
+        return false;
+    }
+
+    for( char const* p = s.c_str(); *p; ++p )
+    {
+        unsigned char ch = static_cast<unsigned char>( *p );
+
+        if( ch < '0' || ch > '9' )
+        {
+            return false;
+        }
+
+        if( v > UINT_MAX / 10 )
+        {
+            return false;
+        }
+
+        unsigned q = static_cast<unsigned>( ch - '0' );
+
+        if( v == UINT_MAX / 10 && q > UINT_MAX % 10 )
+        {
+            return false;
+        }
+
+        v = v * 10 + q;
+    }
+
+    return true;
+}
+
+} // namespace thread_detail
+} // namespace boost
+
+#endif // #ifndef BOOST_THREAD_DETAIL_STRING_TO_UNSIGNED_HPP_INCLUDED
diff --git a/test/Jamfile.v2 b/test/Jamfile.v2
index 4d55815a..3f81bc07 100644
--- a/test/Jamfile.v2
+++ b/test/Jamfile.v2
@@ -1103,5 +1103,6 @@ rule generate_self_contained_header_tests
     test-suite detail
     :
           [ run detail/string_trim_test.cpp ]
+          [ run detail/string_to_unsigned_test.cpp ]
     ;
 }
diff --git a/test/detail/string_to_unsigned_test.cpp b/test/detail/string_to_unsigned_test.cpp
new file mode 100644
index 00000000..7fababa6
--- /dev/null
+++ b/test/detail/string_to_unsigned_test.cpp
@@ -0,0 +1,55 @@
+// Copyright 2023 Peter Dimov
+// Distributed under the Boost Software License, Version 1.0.
+// https://www.boost.org/LICENSE_1_0.txt
+
+#include <boost/thread/detail/string_to_unsigned.hpp>
+#include <boost/core/lightweight_test.hpp>
+
+int main()
+{
+    using boost::thread_detail::string_to_unsigned;
+
+    unsigned v;
+
+    BOOST_TEST_NOT( string_to_unsigned( "", v ) ) && BOOST_TEST_EQ( v, 0 );
+    BOOST_TEST_NOT( string_to_unsigned( " ", v ) ) && BOOST_TEST_EQ( v, 0 );
+    BOOST_TEST_NOT( string_to_unsigned( "+1", v ) ) && BOOST_TEST_EQ( v, 0 );
+    BOOST_TEST_NOT( string_to_unsigned( "-1", v ) ) && BOOST_TEST_EQ( v, 0 );
+    BOOST_TEST_NOT( string_to_unsigned( "abc", v ) ) && BOOST_TEST_EQ( v, 0 );
+
+    BOOST_TEST( string_to_unsigned( "0", v ) ) && BOOST_TEST_EQ( v, 0 );
+    BOOST_TEST( string_to_unsigned( "1", v ) ) && BOOST_TEST_EQ( v, 1 );
+    BOOST_TEST( string_to_unsigned( "12", v ) ) && BOOST_TEST_EQ( v, 12 );
+    BOOST_TEST( string_to_unsigned( "123", v ) ) && BOOST_TEST_EQ( v, 123 );
+    BOOST_TEST( string_to_unsigned( "1234", v ) ) && BOOST_TEST_EQ( v, 1234 );
+    BOOST_TEST( string_to_unsigned( "12345", v ) ) && BOOST_TEST_EQ( v, 12345 );
+    BOOST_TEST( string_to_unsigned( "123456", v ) ) && BOOST_TEST_EQ( v, 123456 );
+    BOOST_TEST( string_to_unsigned( "1234567", v ) ) && BOOST_TEST_EQ( v, 1234567 );
+    BOOST_TEST( string_to_unsigned( "12345678", v ) ) && BOOST_TEST_EQ( v, 12345678 );
+    BOOST_TEST( string_to_unsigned( "123456789", v ) ) && BOOST_TEST_EQ( v, 123456789 );
+    BOOST_TEST( string_to_unsigned( "1234567890", v ) ) && BOOST_TEST_EQ( v, 1234567890 );
+    BOOST_TEST_NOT( string_to_unsigned( "12345678901", v ) ) && BOOST_TEST_EQ( v, 1234567890 );
+    BOOST_TEST_NOT( string_to_unsigned( "123456789012", v ) ) && BOOST_TEST_EQ( v, 1234567890 );
+
+    BOOST_TEST( string_to_unsigned( "4294967295", v ) ) && BOOST_TEST_EQ( v, 4294967295 );
+    BOOST_TEST_NOT( string_to_unsigned( "4294967296", v ) ) && BOOST_TEST_EQ( v, 429496729 );
+
+    BOOST_TEST( string_to_unsigned( "01", v ) ) && BOOST_TEST_EQ( v, 1 );
+    BOOST_TEST( string_to_unsigned( "001", v ) ) && BOOST_TEST_EQ( v, 1 );
+    BOOST_TEST( string_to_unsigned( "0001", v ) ) && BOOST_TEST_EQ( v, 1 );
+    BOOST_TEST( string_to_unsigned( "00001", v ) ) && BOOST_TEST_EQ( v, 1 );
+    BOOST_TEST( string_to_unsigned( "000001", v ) ) && BOOST_TEST_EQ( v, 1 );
+    BOOST_TEST( string_to_unsigned( "0000001", v ) ) && BOOST_TEST_EQ( v, 1 );
+    BOOST_TEST( string_to_unsigned( "00000001", v ) ) && BOOST_TEST_EQ( v, 1 );
+    BOOST_TEST( string_to_unsigned( "000000001", v ) ) && BOOST_TEST_EQ( v, 1 );
+    BOOST_TEST( string_to_unsigned( "0000000001", v ) ) && BOOST_TEST_EQ( v, 1 );
+    BOOST_TEST( string_to_unsigned( "00000000001", v ) ) && BOOST_TEST_EQ( v, 1 );
+    BOOST_TEST( string_to_unsigned( "000000000001", v ) ) && BOOST_TEST_EQ( v, 1 );
+    BOOST_TEST( string_to_unsigned( "0000000000001", v ) ) && BOOST_TEST_EQ( v, 1 );
+    BOOST_TEST( string_to_unsigned( "00000000000001", v ) ) && BOOST_TEST_EQ( v, 1 );
+
+    BOOST_TEST_NOT( string_to_unsigned( "1a", v ) ) && BOOST_TEST_EQ( v, 1 );
+    BOOST_TEST_NOT( string_to_unsigned( "2 ", v ) ) && BOOST_TEST_EQ( v, 2 );
+
+    return boost::report_errors();
+}