Question

I am facing one issue related to pthread_cancel. Please see the code below:

void* func(void *arg)
{
    while(1)
    {
        sleep(2);
    }
}

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

int main()
{
    void *status;
    pthread_t thr_Var;
    pthread_setcancelstate(PTHREAD_CANCEL_DISABLE,NULL);
    pthread_create(&thr_Var,NULL,func,NULL);
    pthread_cancel(thr_Var);
    pthread_join(thr_Var,&status);   
    return 0;
}

My doubt is even if i disable the cancel state, still pthread_cancel is working and thread is getting terminated.
Any help will be appreciated

Answer 1

pthread_setcancelstate sets the cancelability type of the calling thread, i.e. the main thread in your case. So if you want to make the newly created thread non-cancelable you should call that function from within the context of that thread.

See man 3 pthread_setcancelstate

Note that while Linux pthreads implementation permits a NULL oldstate pointer, POSIX, however, does not specify that, so it’s best to provide a pointer for oldsate.