POSIX Thread Creation

The following code demonstrates creation of threads using POSIX thread libraries in Linux environment.

#include <pthread.h>

#include <stdlib.h>

#include<stdio.h>

///////function for thread-1 /////////////

void *new_thread1(void *thread_args)

{

     int i,j;

     for (j=0;j<10;j++)

     {

           printf("am in new thread-1\n");

           for(i=0;i<500000000;i++);

     }

     return NULL;

}

///////function for thread-2 /////////////

void *new_thread2(void *thread_args)

{

     int i,j;

     for (j=0;j<10;j++)

     {

           printf("am in new thread-2\n");

           for(i=0;i<500000000;i++);

     }

     return NULL;

}

///////main thread /////////////

int main()

{

     int i,j;

     pthread_t tcb1, tcb2;

     if (pthread_create( &tcb1, NULL, new_thread1, NULL))

     {

           printf("error\n");

           return -1;

     }

     if (pthread_create( &tcb2, NULL, new_thread2, NULL))

     {

           printf("error\n");

          return -1;

     }

     for(j=0;j<10;j++)

     {

           printf("am in main thread\n");

           for(i=0;i<800000000;i++);

     }

     pthread_join(tcb1, NULL);

     pthread_join(tcb2, NULL);

     return 1;

}

Here the pthread_create() function is used to create child threads along with following parameters:

·         tcb:  a structure which holds fields of the newly created thread (tcb1).

·         task_function:  pointer to a function which does the actually task of the child thread (new_thread1).

The pthread_join function monitors the termination of child threads and returning the control to parent thread.

The above code (tth.c) can be compiled and executed as follows:

         gcc tth.c tth.o –lpthread

        ./tth

Working of the above code is as below: