[Boost-bugs] [Boost C++ Libraries] #6145: MinGW / GCC 4.6.1 warns about conflicts between Boost.Thread and Boost.InterProcess (Win32 C API)

Subject: [Boost-bugs] [Boost C++ Libraries] #6145: MinGW / GCC 4.6.1 warns about conflicts between Boost.Thread and Boost.InterProcess (Win32 C API)
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2011-11-18 18:28:21

#6145: MinGW / GCC 4.6.1 warns about conflicts between Boost.Thread and
Boost.InterProcess (Win32 C API)
--------------------------------------------------------+-------------------
 Reporter:  Cyril Othenin-Girard <cog@…>                |       Owner:  igaztanaga  
     Type:  Bugs                                        |      Status:  new         
Milestone:  To Be Determined                            |   Component:  interprocess
  Version:  Boost 1.48.0                                |    Severity:  Problem     
 Keywords:  MinGW interprocess thread warning conflict  |  
--------------------------------------------------------+-------------------
 I compile boost-1.48 with GCC 4.6.1 using MinGW-32 3.10 on Windows XP.

 My compiling options are :
 {{{
 g++ -std=c++0x
 }}}

 I encounter the following conflicts :

 {{{
 ~/boost-1.48/interprocess/detail/win32_api.hpp:808:116: warning:
 declaration of 'void*
 boost::interprocess::winapi::CreateMutexA(boost::interprocess::winapi::interprocess_security_attributes*,
 int, const char*)' with C language linkage [enabled by default]
 ~/boost-1.48/thread/win32/thread_primitives.hpp:119:55: warning: conflicts
 with previous declaration 'void*
 boost::detail::win32::CreateMutexA(boost::detail::win32::_SECURITY_ATTRIBUTES*,
 int, const char*)' [enabled by default]
 }}}
 {{{
 ~/boost-1.48/interprocess/detail/win32_api.hpp:813:127: warning:
 declaration of 'void*
 boost::interprocess::winapi::CreateSemaphoreA(boost::interprocess::winapi::interprocess_security_attributes*,
 long int, long int, const char*)' with C language linkage [enabled by
 default]
 ~/boost-1.48/thread/win32/thread_primitives.hpp:120:55: warning: conflicts
 with previous declaration 'void*
 boost::detail::win32::CreateSemaphoreA(boost::detail::win32::_SECURITY_ATTRIBUTES*,
 long int, long int, const char*)' [enabled by default]
 }}}

 The problem looks like closed tickets #4217 and #5030.

 It looks like "extern C" modifier make the compiler to ignore namespace
 declarations, hence the conflicts.

 For example, discarding namespaces, '''Boost.Thread''' declares
 CreateMutexA() like this :
 {{{
 extern "C"
 {
     struct _SECURITY_ATTRIBUTES;
     __declspec(dllimport) void* __stdcall
 CreateMutexA('''boost::detail::win32::_SECURITY_ATTRIBUTES'''*,int,char
 const*);
 }
 }}}
 whereas '''Boost.Interprocess''' declares it like this :
 {{{
 struct interprocess_security_attributes
 {
    unsigned long nLength;
    void *lpSecurityDescriptor;
    int bInheritHandle;
 };
 extern "C" __declspec(dllimport) void * __stdcall
 CreateMutexA('''boost::interprocess::winapi::interprocess_security_attributes'''*,
 int, const char *);
 }}}

 To avoid the compiler warnings, the same type should be used for the first
 parameter of CreateMutexA().

-- 
Ticket URL: <https://svn.boost.org/trac/boost/ticket/6145>
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