Question

I’m attempting to do some basic parallelisation using _beginthreadex, and passing parameters as per an example I was given, but it won’t work.

Any ideas?

#include <iostream> 
#include <process.h>



void MyThread(void *data)
{
    std::cout << "Hello World!"; 
}

int main()
{
    _beginthreadex(NULL, 0, MyThread, NULL, 0, NULL); 
    while(true);
}

EDIT:

Why won’t passing NULL as an argument work? (Since the function takes no arguments anyway?)

Passing NULL as an arguments list worked fine with _beginthread.

Answer 1

Your code has two errors in it, neither of which are related to the parameter to the thread function — NULL is fine for that, as you surmised.

The problems are in the signature of the thread function, and the error you are getting points this out. Firstly, it must be a __stdcall function, and secondly it must return an unsigned int. Your function is __cdecl and returns void.

unsigned __stdcall MyThread(void *data)
{
    std::cout << "Hello World!"; 
    return 0;
}

should fix the problem for you.