how to close the thread externally

i created one thread in main(). I have while in thread function.

I want close the thread in main after some time. How can i close it.

Please help me.

Regards,
Nagendra R

Try pthread_cancel().

If that does not work, then try designing your s/w such that you can notify the thread via some other means (ie setting a semaphore or other data type).

P.S. A simple example:

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

void* run(void* arg)
{
   while (1) {
      printf("The thread is running.\n");
      sleep(2);
   }

   return 0;
}

int main(void)
{
   pthread_t tid;

   pthread_create(&tid, 0, run, 0);

   sleep(10);

   pthread_cancel(tid);   // thread will stop executing here.

   sleep(4);

   return 0;
}

I tried like this . But does not work.

Here after cancel the thread, i delete the object passing to the thread function. Then I am getting crash because it is used by thread function after cancel the function also.

Please help me to solve this problem in another way.

Regards,
Nagendra R

Originally Posted by nagendrar I tried like this . But does not work. Here after cancel the thread, i delete the object passing to the thread function. Then I am getting crash because it is used by thread function after cancel the function also. Please help me to solve this problem in another way. Regards, Nagendra R

Ok, wait for a moment while I put on my ESP-enhancing hat, so that I can visualize your code....

Originally Posted by nagendrar I tried like this . But does not work.

Of course it doesn't. You have opened a can containing more worms than one can possibly imagine. That is a cute way of saying there are many, many potential problems raised by asynchronous canceling of a thread. You're lucky that the program consistently fails. A much worse situation would be if the program ran most of the time, but failed only occasionally. This can easily happen with POSIX threads.

To understand why all this is true, you should run (not walk) to your nearest bookseller and buy David R. Butenhof's excellent book Programming with POSIX Threads, published by Addison Wesley. (The copy I have of a similar book published by O'Reilly looks complete, but is sufficiently incomplete as to be dangerous.)

When you have read this book, you may find it easier simply to rewrite your code so that the thread that is to be canceled somehow finds out about this desire, and terminates by itself, gracefully.

Hope this helps.