Question

I am trying to compile some C++ code that uses threads:

#include <iostream>
#include <thread>
void hello()
{
    std::cout<<"Hello Concurrent World\n";
}

int _main(int argc, _TCHAR* argv[])
{
    std::thread t(hello);
    t.join();
    return 0;
}

I get errors when compiling:

c:\temp\app1\app1\app1.cpp(6): fatal error C1083: Cannot open 
include file: 'thread': No such file or directory


~/Documents/C++ $ g++ -o thread1 thread1.cpp -D_REENTRANT -lpthread
In file included from /usr/include/c++/4.5/thread:35:0,
                 from thread1.cpp:2:
/usr/include/c++/4.5/bits/c++0x_warning.h:31:2: error: #error This file 
requires compiler and library support for the upcoming ISO C++ standard, 
C++0x. This support is currently experimental, and must be enabled with 
the -std=c++0x or -std=gnu++0x compiler options.

How do I fix these errors?

Answer 1

<thread> and standard threading support is a new feature (defined in the C++11 standard). As for g++, you have to enable it adding -std=c++0x to the command line, as explained in the error message.

Also, you are using a nonstandard (Microsoft-specific) main, use the “classic” main and normal char:

// thread1.cpp
#include <iostream>
#include <thread>

void hello()
{
    std::cout<<"Hello Concurrent World\n";
}

int main(int argc, char * argv[])
{
    std::thread t(hello);
    t.join();

    return 0;
}

Notice that not all C++11 features are available in current compilers; as far as g++ is concerned, you can find the status of their implementation here.