Question

use pthread_create to create limited number of threads running concurrently
Successfully compile and run

However, after adding function pointer array to run the function, Segmentation fault

Where is wrong?

workserver number: 0
Segmentation fault

void* workserver(void *arg)
{
int status;
while(true)
{
    printf("workserver number: %d\n", (int)arg);
    (* job_queue[(int)arg])();
    sleep(3);

    status = pthread_mutex_lock(&data.mutex);
    if(status != 0)
        printf("%d lock mutex", status);
    data.value = 1;
    status = pthread_cond_signal(&data.cond);
    if(status != 0)
        printf("%d signal condition", status);
    status = pthread_mutex_unlock(&data.mutex);
    if(status != 0)
        printf("%d unlock mutex", status);
}
}


void jobadd(void (*job)())
{   
    for(int i; i<3; i++)
    {
        if(idle[i] == 0)
        {
            job_queue[i] = job;
            job;
            idle[i] = 1;
        }
    }
}
void func1()
{
    printf("func1 run");
}
void func2()
{
    printf("func2 run");
}
void func3()
{
    printf("func3 run");
}
void func4()
{
    printf("func4 run");
}

int main(int argc, char* argv[])
{
    jobadd(func1);
    jobadd(func2);
    jobadd(func3);
    jobrun();
    return 0;
}

initialize function pointer array with jobadd function

Answer 1

add more detail in the question

job_queue[i] = job

just assign a function to the function pointer array

as can not assign function pointer array directly to pthread_create