C++ mutex in namespace std does not name a type

Question

I\'m writing a simple C++ program to demonstrate the use of locks. I am using codeblocks and gnu gcc compiler.

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Answer 1

I fixed it by following steps:

• Project > Build option...
• The default selected compiler: GNU GCC Compiler
• On tab "Compiler settings / Compiler flags", check option "Have g++ follow the C++11 ISO C++ language standard [-std=c++11]"

Answer 2

I got the same error with gcc4.7.7.

After adding "-std=c++0x", it is fixed.

Answer 3

I encountered this same problem when using MingW-W64 7.2.0. I tested out several different Windows builds from the mingw-64 download page, and found that MinGW-W64 GCC-8.1.0 supports mutex and contains the pthread library. When installing, I selected the following options:

• x86_64
• posix
• seh

My multi-threaded code based on pthreads now compiles and runs cleanly on both Windows and Linux with no changes.

This version is leaner than the 7.3.0 build I was using because it doesn't have a CygWin environment or package manager. I also copied mingw32-make.exe to make.exe so my Makefile wouldn't need to be modified. The installer creates a "Run terminal" link in the Windows Start Menu.

Answer 4

This has now been included in MingW (Version 2013072300). To include it you have to select the pthreads package in the MinGW Installation Manager.

Answer 5

Many classes of the standard thread library can be replaced with the boost ones. A very easy workaround is to change the entire standard mutex file with a couple of lines.

#include <boost/thread.hpp>

namespace std
{
   using boost::mutex;
   using boost::recursive_mutex;
   using boost::lock_guard;
   using boost::condition_variable;
   using boost::unique_lock;
   using boost::thread;
}

And do not forget to link against boost thread library.

Answer 6

Use POSIX threading model for MINGW:

$ sudo update-alternatives --config i686-w64-mingw32-gcc
<choose i686-w64-mingw32-gcc-posix from the list>

$ sudo update-alternatives --config i686-w64-mingw32-g++
<choose i686-w64-mingw32-g++-posix from the list>

$ sudo update-alternatives --config x86_64-w64-mingw32-gcc
<choose x86_64-w64-mingw32-gcc-posix from the list>

$ sudo update-alternatives --config x86_64-w64-mingw32-g++
<choose x86_64-w64-mingw32-g++-posix from the list>

See also: mingw-w64 threads: posix vs win32