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Enabling std::thread and friends in MinGW GCC 4.7

This patch enables the C++11 thread, mutex and future features using pthread-w32 as the implementation (which comes bundled with MinGW).

This assumes you are using the official MinGW distribution.
If you are applying this patch to a version of MinGW GCC later than 4.7, you should examine and apply the patches rather than using the zip file.

• Download mingw-thread-gcc4.7.0.zip which contains two patched include files and the libstdc++ threading source files.
  (Original patches: gthr.h, gthr-posix.h)
• Copy the two files from the include directory in the zip file to the following directory: C:\mingw\lib\gcc\mingw32\4.7.0\include\c++\mingw32\bits (replace C:\mingw\ with the appropriate directory)
  (untested on 4.7.1+, but replace 4.7.0 with the correct version number if you're brave, otherwise try the patches)
• Build the (unmodified) libstdc++ files included in the zip file, this will create and install libstdthread.a: mingw32-make install MINGWDIR=C:\mingw\ (if you are building on non-Windows, if even possible, modify the Makefile first)
• When building programs which use threads, mutexes or futures, link with libstdthread.a and libpthread.a: -lstdthread -lpthread (-lpthreadGC2 should be equivalent to -lpthread)

NOTE: "libstdthread" is a completely unofficial name, so should only be part of your local build command.
On gcc toolchains already supporting threads, it is a part of libstdc++ and linked by default for C++ projects.

Update, 14 September 2012:

All patches here are released in to the public domain, and free for use for any purpose.

Please note that this patch cannot enable thread safety throughout libstdc++, as it is applied post-build. This means some conforming programs that use standard library facilities from multiple threads may result in unexpected behaviour. It has also been known to cause problems with other libstdc++ components, breaking std::fstream being one noted example.

You may prefer to look in to the mingw-w64 stdthread branch, which is working to enable std::thread support properly in MinGW.

Tags: MinGW, C++, libstdc++, thread

Author: Julian Smythe