A semaphore implementation with C11 threading libraries

semaphore.c

#include <threads.h>

typedef struct {
   int value;
   mtx_t mutex;
   cnd_t cv;
} sem_t;

int sem_init(sem_t *sem, int value) {
    int result;
    if (mtx_init(&sem->mutex, mtx_plain) == thrd_error)
        return thrd_error;
    if ((result = cnd_init(&sem->cv)) == thrd_error || result == thrd_nomem)
        return thrd_error;
    sem->value = value;
    return thrd_success;
}

void sem_destroy(sem_t *sem) {
    mtx_destroy(&sem->mutex);
    cnd_destroy(&sem->cv);
    sem->value = 0;
}

int sem_wait(sem_t *sem) {
    if (mtx_lock(&sem->mutex) == thrd_error)
        return thrd_error;
    while (sem->value == 0) {
        if (cnd_wait(&sem->cv, &sem->mutex) == thrd_error)
            return thrd_error;
    }
    sem->value--;
    if (mtx_unlock(&sem->mutex) == thrd_error)
        return thrd_error;
    return thrd_success;
}

int sem_post(sem_t *sem) {
    if (mtx_lock(&sem->mutex) == thrd_error)
        return thrd_error;
    sem->value++;
    if (sem->value > 0)
        if (cnd_signal(&sem->cv) == thrd_error)
            return thrd_error;
    if (mtx_unlock(&sem->mutex) == thrd_error)
        return thrd_error;
    return thrd_success;
}