diff --git a/include/boost/interprocess/detail/os_file_functions.hpp b/include/boost/interprocess/detail/os_file_functions.hpp
index 79d47fa..7f389c3 100644
--- a/include/boost/interprocess/detail/os_file_functions.hpp
+++ b/include/boost/interprocess/detail/os_file_functions.hpp
@@ -101,9 +101,23 @@ inline file_handle_t file_handle_from_mapping_handle(mapping_handle_t hnd)
 {  return hnd.handle; }
 
 template<class CharT>
-inline bool create_directory(const CharT *path, bool = false)
+inline bool create_directory(const CharT *path)
 {  return winapi::create_directory(path); }
 
+template<class CharT>
+inline bool open_or_create_directory(const CharT *path)
+{
+   //If fails, check that it's because it already exists
+   return create_directory(path)
+      ||  error_info(system_error_code()).get_error_code() == already_exists_error;
+}
+
+template<class CharT>
+inline bool open_or_create_shared_directory(const CharT *path)
+{
+   return open_or_create_directory(path);
+}
+
 template <class CharT>
 inline bool remove_directory(const CharT *path)
 {  return winapi::remove_directory(path); }
@@ -493,10 +507,23 @@ inline mapping_handle_t mapping_handle_from_file_handle(file_handle_t hnd)
 inline file_handle_t file_handle_from_mapping_handle(mapping_handle_t hnd)
 {  return hnd.handle; }
 
-inline bool create_directory(const char *path, bool is_shared_dir = false)
+inline bool create_directory(const char *path)
 {
-   ::mode_t m = is_shared_dir ? 01777 : 0777;
-   return ::mkdir(path, m) == 0 && ::chmod(path, m) == 0;
+   ::mode_t m = ::mode_t(0777);
+   return ::mkdir(path, m) == 0;
+}
+
+inline bool open_or_create_directory(const char *path)
+{
+   ::mode_t m = ::mode_t(0777);
+   return ::mkdir(path, m) == 0 || (errno == EEXIST);
+}
+
+inline bool open_or_create_shared_directory(const char *path)
+{
+   ::mode_t m = ::mode_t(01777);
+   const bool created_or_exists = (::mkdir(path, m) == 0) || (errno == EEXIST);
+   return created_or_exists && (::chmod(path, m) == 0);
 }
 
 inline bool remove_directory(const char *path)
@@ -785,18 +812,6 @@ inline bool delete_subdirectories(const std::string &refcstrRootDirectory, const
 
 #endif   //#if defined (BOOST_INTERPROCESS_WINDOWS)
 
-inline bool open_or_create_directory(const char *dir_name, bool is_shared_dir = false)
-{
-   //If fails, check that it's because it already exists
-   if(!create_directory(dir_name, is_shared_dir)){
-      error_info info(system_error_code());
-      if(info.get_error_code() != already_exists_error){
-         return false;
-      }
-   }
-   return true;
-}
-
 inline std::string get_temporary_path()
 {
    std::size_t required_len = 0;
diff --git a/include/boost/interprocess/detail/portable_intermodule_singleton.hpp b/include/boost/interprocess/detail/portable_intermodule_singleton.hpp
index 12fd0e7..32e196a 100644
--- a/include/boost/interprocess/detail/portable_intermodule_singleton.hpp
+++ b/include/boost/interprocess/detail/portable_intermodule_singleton.hpp
@@ -52,7 +52,7 @@ static void create_tmp_subdir_and_get_pid_based_filepath
    create_shared_dir_and_clean_old(s);
    s += "/";
    s += subdir_name;
-   if(!open_or_create_directory(s.c_str(), true)){
+   if(!open_or_create_shared_directory(s.c_str())){
       error_info err = system_error_code();
       throw interprocess_exception(err);
    }
diff --git a/include/boost/interprocess/detail/shared_dir_helpers.hpp b/include/boost/interprocess/detail/shared_dir_helpers.hpp
index 17c4fd8..8d9d36f 100644
--- a/include/boost/interprocess/detail/shared_dir_helpers.hpp
+++ b/include/boost/interprocess/detail/shared_dir_helpers.hpp
@@ -209,22 +209,18 @@ inline void create_shared_dir_and_clean_old(std::basic_string<CharT> &shared_dir
       get_shared_dir_root(root_shared_dir);
 
       //If fails, check that it's because already exists
-      if(!create_directory(root_shared_dir.c_str(), true)){
+      if(!open_or_create_shared_directory(root_shared_dir.c_str())){
          error_info info(system_error_code());
-         if(info.get_error_code() != already_exists_error){
-            throw interprocess_exception(info);
-         }
+         throw interprocess_exception(info);
       }
 
       #if defined(BOOST_INTERPROCESS_HAS_KERNEL_BOOTTIME)
          get_shared_dir(shared_dir);
 
          //If fails, check that it's because already exists
-         if(!create_directory(shared_dir.c_str(), true)){
+         if(!open_or_create_shared_directory(shared_dir.c_str())){
             error_info info(system_error_code());
-            if(info.get_error_code() != already_exists_error){
-               throw interprocess_exception(info);
-            }
+            throw interprocess_exception(info);
          }
          //Now erase all old directories created in the previous boot sessions
          std::basic_string<CharT> subdir = shared_dir;
diff --git a/test/windows_eventlog_stamp_shared_memory_test.cpp b/test/windows_eventlog_stamp_shared_memory_test.cpp
index 0ae8755..16a0d45 100644
--- a/test/windows_eventlog_stamp_shared_memory_test.cpp
+++ b/test/windows_eventlog_stamp_shared_memory_test.cpp
@@ -38,7 +38,7 @@ inline void get_shared_dir(std::string &shared_dir)
    shared_dir += "/boostipctesteventlog_";
    shared_dir += boost::interprocess::test::get_process_id_name();
    if(!dir_created)
-      ipcdetail::create_directory(shared_dir.c_str(), true);
+      ipcdetail::open_or_create_shared_directory(shared_dir.c_str());
    dir_created = true;
 }
 
@@ -48,7 +48,7 @@ inline void get_shared_dir(std::wstring &shared_dir)
    shared_dir += L"/boostipctesteventlog_";
    shared_dir += boost::interprocess::test::get_process_id_wname();
    if(!dir_created)
-      ipcdetail::create_directory(shared_dir.c_str(), true);
+      ipcdetail::open_or_create_shared_directory(shared_dir.c_str());
    dir_created = true;
 }
 
diff --git a/test/windows_shared_dir_func.cpp b/test/windows_shared_dir_func.cpp
index 2cb1313..e2f1898 100644
--- a/test/windows_shared_dir_func.cpp
+++ b/test/windows_shared_dir_func.cpp
@@ -31,7 +31,7 @@ inline void get_shared_dir(std::string &shared_dir)
    shared_dir += "/boostipctest_";
    shared_dir += boost::interprocess::test::get_process_id_name();
    if(!dir_created)
-      ipcdetail::create_directory(shared_dir.c_str(), true);
+      ipcdetail::open_or_create_shared_directory(shared_dir.c_str());
    dir_created = true;
 }
 
@@ -41,7 +41,7 @@ inline void get_shared_dir(std::wstring &shared_dir)
    shared_dir += L"/boostipctest_";
    shared_dir += boost::interprocess::test::get_process_id_wname();
    if(!dir_created)
-      ipcdetail::create_directory(shared_dir.c_str(), true);
+      ipcdetail::open_or_create_shared_directory(shared_dir.c_str());
    dir_created = true;
 }