Question

I have 2 threads.
My goal is that the first one that terminate his own execution, have to stop the other thread.
Is it possible?

I have this code:

#include <stdio.h>
#include <pthread.h>
#include <sys/types.h>

void* start1(void* arg)
{
  printf("I'm just born 1\n");
  int i = 0;
  for (i = 0;i < 100;i++)
  {
    printf("Thread 1\n");
  }
  printf("I'm dead 1\n");
  pthread_exit(0);
}

void* start2(void* arg)
{
  printf("I'm just born 2\n");
  int i = 0;
  for (i = 0;i < 1000;i++)
  {
    printf("Thread 2\n");
  }
  printf("I'm dead 2\n");
  pthread_exit(0);
}

void* function()
{
  int k = 0;
  int i = 0;
  for (i = 0;i < 50;i++)
  {
    k++;
    printf("I'm an useless function\n");
  }
}   

int main()
{
  pthread_t t, tt;
  int status;
  if (pthread_create(&t, NULL, start1, NULL) != 0)
  {
    printf("Error creating a new thread 1\n");
    exit(1);
  }
  if (pthread_create(&tt, NULL, start2, NULL) != 0)
  {
    printf("Error creating a new thread 2\n");
    exit(1);
  }
  function();
  pthread_join(t, NULL);
  pthread_join(tt, NULL);
  return 0;
}

For example the first thread have to stop the second one.
How can is possible to do that?

Answer 1

Generally it’s not good practice to force a thread to terminate. The clean way to terminate another thread is by setting a flag (visible to both threads) that tells the thread to terminate itself (by returning/exiting immediately).