Linux C/C++互斥锁的使用

c++11中使用了std::lock_guard互斥锁（#include <thread>）。还有一种，我们看看#include <pthread.h>中使用方法。(自我理解锁的范围可随意控制)

操作函数

pthread_mutex_t lock; /* 互斥锁定义 */
pthread_mutex_init(&lock, NULL); /* 动态初始化，    成功返回0，失败返回非0 */
pthread_mutex_t thread_mutex = PTHREAD_MUTEX_INITIALIZER； /* 静态初始化 */
pthread_mutex_lock(&lock); /* 阻塞的锁定互斥锁 */
pthread_mutex_trylock(&thread_mutex)；/* 非阻塞的锁定互斥锁，成功获得互斥锁返回0，如果未能获得互斥锁，立即返回一个错误码 */
pthread_mutex_unlock(&lock)； /* 解锁互斥锁 */
pthread_mutex_destroy(&lock) /* 销毁互斥锁 */

Example

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

static pthread_mutex_t   g_mutex_lock;
static int g_count = 0;

static void *thread_fun_1(void *data)
{
    pthread_mutex_lock(&g_mutex_lock);

    g_count++;
    printf("%s g_count: %d
", __func__, g_count);

    pthread_mutex_unlock(&g_mutex_lock);
}

static void *thread_fun_2(void *data)
{
    pthread_mutex_lock(&g_mutex_lock);

    g_count++;
    printf("%s g_count: %d
", __func__, g_count);

    pthread_mutex_unlock(&g_mutex_lock);
}

static void *thread_fun_3(void *data)
{
    pthread_mutex_lock(&g_mutex_lock);

    g_count++;
    printf("%s g_count: %d
", __func__, g_count);

    pthread_mutex_unlock(&g_mutex_lock);
}

int main(int argc, char const *argv[])
{
    int ret;
    pthread_t pid[3];

    ret = pthread_mutex_init(&g_mutex_lock, NULL);
    if (ret != 0) {
        printf("mutex init failed
");
        return -1;
    }

    pthread_create(&pid[0], NULL, thread_fun_1, NULL);
    pthread_create(&pid[1], NULL, thread_fun_2, NULL);
    pthread_create(&pid[2], NULL, thread_fun_3, NULL);

    pthread_join(pid[0], NULL);
    pthread_join(pid[1], NULL);
    pthread_join(pid[2], NULL);

    pthread_mutex_destroy(&g_mutex_lock);

    return 0;
}