error: 'mutex' in namespace 'std' does not name a type in gcc 4.6.2

Question

Simple program like this

#include <iostream>       // std::cout
#include <thread>         // std::thread
#include <mutex>          // std::mutex

std::mutex mtx;           // mutex for critical section

int main ()
{
     return 0;
}

Tried the following to compile

$ /usr/local/Cellar/gcc46/4.6.4/bin/g++-4.6 -std=gnu++0x -I/usr/local/Cellar/gcc46/4.6.4/gcc/include/c++ -L/usr/local/Cellar/gcc46/4.6.4/gcc/lib temp_mutex.cpp 
temp_mutex.cpp:6:1: error: 'mutex' in namespace 'std' does not name a type

By the way I am compiling on Mac.

Answer 1

It worked for me:

$ g++-4.7 -O2 -Wall -std=c++11 -c mutextest.cc
$ g++-4.6 -O2 -Wall -std=c++0x -c mutextest.cc
$ g++-4.6 -O2 -Wall -std=gnu++0x -c mutextest.cc
$ g++-4.4 -O2 -Wall -std=c++0x -c mutextest.cc
$ g++-4.4 -O2 -Wall -std=gnu++0x -c mutextest.cc

None of these generated any error messages.