pthread_mutex_destroy function

Function

Reference manual

The pthread_mutex_destroy function is used to destroy a mutex object that was previously initialized using pthread_mutex_init. This function releases any resources associated with the mutex.

Syntax

#include <pthread.h>

int pthread_mutex_destroy(pthread_mutex_t *mutex);

Parameters

mutex: A pointer to a variable of type pthread_mutex_t representing the mutex to be destroyed.

Return value

If the mutex is successfully destroyed, the function returns 0.
If an error occurs, a non-zero error code is returned. Possible error codes include EINVAL (invalid mutex) and EBUSY (mutex is locked).

Usage example

In the following example we initialize a global mutex variable mutex using pthread_mutex_init, then we create three threads, each executing the thread_function function. Each thread locks the mutex with pthread_mutex_lock, enters a critical section where it prints its ID, and then unlocks the mutex with pthread_mutex_unlock. After all threads have finished executing, we destroy the mutex using pthread_mutex_destroy. This example demonstrates how to use mutexes to protect critical sections of code from concurrent execution by multiple threads.

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

pthread_mutex_t mutex;

void *thread_function(void *arg)
{
    int *thread_id;

    pthread_mutex_lock(&mutex); // Lock the mutex
    *thread_id = arg;
    printf("Thread %d is inside the critical section\n", *thread_id);
    pthread_mutex_unlock(&mutex); // Unlock the mutex
    return (NULL);
}

int main(void)
{
    pthread_t threads[3];
    int thread_args[3] = {1, 2, 3};

    // Initialize the mutex
    int init_result = pthread_mutex_init(&mutex, NULL);
    if (init_result != 0) {
        fprintf(stderr, "Error initializing mutex: %d\n", init_result);
        return (EXIT_FAILURE);
    }
    // Create three threads
    for (int i = 0; i < 3; i++) {
        int create_result = pthread_create(&threads[i], NULL, thread_function, &thread_args[i]);
        if (create_result != 0) {
            fprintf(stderr, "Error creating thread %d: %d\n", i+1, create_result);
            return (EXIT_FAILURE);
        }
    }
    // Join all threads
    for (int i = 0; i < 3; i++) {
        int join_result = pthread_join(threads[i], NULL);
        if (join_result != 0) {
            fprintf(stderr, "Error joining thread %d: %d\n", i+1, join_result);
            return (EXIT_FAILURE);
        }
    }
    // Destroy the mutex
    int destroy_result = pthread_mutex_destroy(&mutex);
    if (destroy_result != 0) {
        fprintf(stderr, "Error destroying mutex: %d\n", destroy_result);
        return (EXIT_FAILURE);
    }
    printf("All threads have finished executing\n");
    return (EXIT_SUCCESS);
}