Question

Im using Ubuntu 10.10, Code::Blocks with GCC 4.2.

I have written a code like that:

#include <iostream>
#include <stdlib.h>
#include <pthread.h>

using namespace std;

void *thread1proc(void* param){
    while(true)
    cout << "1";

    return 0;
}

int main(){
    pthread_t thread1;

    pthread_create(&thread1,NULL,thread1proc,NULL);
    pthread_join(thread1,NULL);

    cout << "hello";
}

Main starts, creates the thread. But what is weird (for me) is main doesn’t continue running. I expect to see “hello” message on screen and end of the program. Because in Windows, in Delphi it worked for me like that. If “main” is also a thread, why doesn’t it continue running? Is it about POSIX threading?

Thank you.

Answer 1

It stops because you call pthread_join and the thread you are joining “to” has an infinite loop.

From that link:

The pthread_join() function suspends
execution of the calling thread until
the target thread terminates, unless
the target thread has already
terminated.