Question

I’m designing a remake of tetris and need a timer function that runs at the same time as an input function. I’m using pthreads to achieve this, but when I make the call to

pthread_create(&timer, NULL, Timer(), NULL);

I receive an error claiming there is no matching function for call to pthread_create() despite including <pthread.h> in my header.

I noticed that another person asked pretty much the same question here. However, I managed to successfully create pthreads on another computer without doing any of what was suggested to that person.

Below is the source code that I am having problems with. I am not asking for you to rewrite it, but rather inform me what’s wrong. I’ll do the research to fix my code.

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

void *Timer(void) { //I have tried moving the asterisk to pretty much every
                    //possible position and with multiple asterisks. Nothing works

    time_t time1, time2;

    time1 = time(NULL);

    while (time2 - time1 <= 1) {
        time2 = time(NULL);
    }

    pthread_exit(NULL);
}

int main() {

    pthread_t inputTimer;

    pthread_create(&inputTimer, NULL, Timer(), NULL); //Error here

    return 0;
}

Thank you

Answer 1

You need to pass an address of your Timer function, not it’s return value. Thus

pthread_create(&inputTimer, NULL, &Timer, NULL); // These two are equivalent
pthread_create(&inputTimer, NULL, Timer, NULL);

pthread_create expects it’s third argument to have the following type: void *(*)(void*); i.e. a function taking a single argument of void* and returning void*.