How to do it…

1. Define a variable of the type pthread_t to store the thread identifier:

pthread_t tid;

2. Create a thread and pass the identifier that was created in the preceding step to the pthread_create function. The thread is created with the default attributes. Also, specify a function that needs to be executed to create the thread:

pthread_create(&tid, NULL, runThread, NULL);

3. In the function, you will be displaying a text message to indicate that the thread has been created and is running:

printf("Running Thread \n");

4. Invoke a for loop to display the sequence of numbers from 1 to 5 through the running thread:

for(i=1;i<=5;i++) printf("%d\n",i);

5. Invoke the pthread_join method in the main function to make the main method wait until the thread completes its task:

pthread_join(tid, NULL);

The createthread.c program for creating a thread and making it perform a task is as follows:

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

void *runThread(void *arg)
{
    int i;
    printf("Running Thread \n");
    for(i=1;i<=5;i++) printf("%d\n",i);
    return NULL;
}

int main()
{
    pthread_t tid;
    printf("In main function\n");
    pthread_create(&tid, NULL, runThread, NULL);
    pthread_join(tid, NULL);
    printf("Thread over\n");
    return 0;
}

Now, let's go behind the scenes.