/*
* Simple semaphore implementation, P() and V().
*
- * Copyright (C) 2011 Simon Ruderich
+ * Copyright (C) 2011-2013 Simon Ruderich
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
#include "sem.h"
-#include <stdlib.h>
#include <pthread.h>
+#include <stdlib.h>
struct SEM {
};
SEM *sem_init(int init_value) {
- SEM *sem = (SEM *)malloc(sizeof(SEM));
- if (NULL == sem) {
+ SEM *sem = malloc(sizeof(*sem));
+ if (sem == NULL) {
return NULL;
}
- if (0 != pthread_mutex_init(&sem->mutex, NULL)) {
+ if (pthread_mutex_init(&sem->mutex, NULL) != 0) {
free(sem);
return NULL;
}
- if (0 != pthread_cond_init(&sem->condition, NULL)) {
+ if (pthread_cond_init(&sem->condition, NULL) != 0) {
pthread_mutex_destroy(&sem->mutex);
free(sem);
return NULL;
}
int sem_del(SEM *sem) {
- if (NULL == sem) {
+ if (sem == NULL) {
return 0;
}
- if (0 != pthread_mutex_destroy(&sem->mutex)) {
+ if (pthread_mutex_destroy(&sem->mutex) != 0) {
free(sem);
return -1;
}
- if (0 != pthread_cond_destroy(&sem->condition)) {
+ if (pthread_cond_destroy(&sem->condition) != 0) {
free(sem);
return -1;
}
void P(SEM *sem) {
pthread_mutex_lock(&sem->mutex);
- while (0 == sem->value) {
+ while (sem->value <= 0) {
pthread_cond_wait(&sem->condition, &sem->mutex);
}
sem->value--;