pthread_equal() in C with example

Prerequisite : Multithreading, pthread_self() in C with Example

pthread_equal() = This compares two thread which is equal or not. This function compares two thread identifiers. It return ‘0’ and non zero value. If it is equal then return non zero value else return 0.

Syntax:- int pthread_equal (pthread_t t1, pthread_t t2);

First Method :- Compare with self thread

// C program to demonstrate working of pthread_equal() 
#include <stdio.h> 
#include <stdlib.h> 
#include <unistd.h> 
#include <sys/types.h> 
#include <pthread.h> 
  
pthread_t tmp_thread; 
  
void* func_one(void* ptr) 
{ 
    // in this field we can compare two thread 
    // pthread_self gives a current thread id 
    if (pthread_equal(tmp_thread, pthread_self())) { 
        printf("equal\n"); 
    } else { 
        printf("not equal\n"); 
    } 
} 
  
// driver code 
int main() 
{ 
    // thread one 
    pthread_t thread_one; 
  
    // assign the id of thread one in temporary 
    // thread which is global declared   r 
    tmp_thread = thread_one; 
  
    // create a thread 
    pthread_create(&thread_one, NULL, func_one, NULL); 
  
    // wait for thread 
    pthread_join(thread_one, NULL); 
} 

Output:

equal

Second Method :- Compare with other thread

// C program to demonstrate working of pthread_equal() 
#include <stdio.h> 
#include <stdlib.h> 
#include <unistd.h> 
#include <sys/types.h> 
#include <pthread.h> 
  
// global declared pthread_t variable 
pthread_t tmp_thread; 
  
void* func_one(void* ptr) 
{ 
    tmp_thread = pthread_self(); // assign the id of thread one in 
    // temporary thread which is global declared 
} 
  
void* func_two(void* ptr) 
{ 
    pthread_t thread_two = pthread_self(); 
  
    // compare two thread 
    if (pthread_equal(tmp_thread, thread_two)) { 
        printf("equal\n"); 
    } else { 
        printf("not equal\n"); 
    } 
} 
  
int main() 
{ 
    pthread_t thread_one, thread_two; 
  
    // creating thread one 
    pthread_create(&thread_one, NULL, func_one, NULL); 
  
    // creating thread two 
    pthread_create(&thread_two, NULL, func_two, NULL); 
  
    // wait for thread one 
    pthread_join(thread_one, NULL); 
  
    // wait for thread two 
    pthread_join(thread_two, NULL); 
} 

Output:

not equal

This article is contributed by Devanshu Agarwal. If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.geeksforgeeks.org or mail your article to contribute@geeksforgeeks.org. See your article appearing on the GeeksforGeeks main page and help other Geeks.

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