pthread_equal() function is used to check whether two threads are equal. It returns 0 or non-zero value. It returns non-zero value for equal threads, 0 otherwise. The syntax of this function is as follows:
int pthread_equal (pthread_t th1, pthread_t th2);
Now let’s see what pthread_equal() actually does. In the first case, we check the self-thread to check the result.
#include <stdio.h> #include <stdlib.h> #include <unistd.h> #include <sys/types.h> #include <pthread.h> pthread_t sample_thread; void* my_thread_function(void* p) { if (pthread_equal(sample_thread, pthread_self())) { //pthread_self will return current thread id printf("Threads are equal</p><p>"); } else { printf("Threads are not equal</p><p>"); } } main() { pthread_t th1; sample_thread = th1; //assign the thread th1 to another thread object pthread_create(&th1, NULL, my_thread_function, NULL); //create a thread using my thread function pthread_join(th1, NULL); //wait for joining the thread with the main thread }
Threads are equal
Now if we compare between two different threads, we will see the result.
#include <stdio.h> #include <stdlib.h> #include <unistd.h> #include <sys/types.h> #include <pthread.h> pthread_t sample_thread; void* my_thread_function1(void* ptr) { sample_thread = pthread_self(); //assign the id of the thread 1 } void* my_thread_function2(void* p) { if (pthread_equal(sample_thread, pthread_self())) { //pthread_self will return current thread id printf("Threads are equal</p><p>"); } else { printf("Threads are not equal</p><p>"); } } main() { pthread_t th1, th2; pthread_create(&th1, NULL, my_thread_function1, NULL); //create a thread using my_thread_function1 pthread_create(&th1, NULL, my_thread_function2, NULL); //create a thread using my_thread_function2 pthread_join(th1, NULL); //wait for joining the thread with the main thread pthread_join(th2, NULL); }
Threads are not equal
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