Linux C/C++互斥鎖的使用

c++11中使用了std::lock_guard互斥鎖（#include <thread>）。還有一種，我們看看#include <pthread.h>中使用方法。(自我理解鎖的范圍可隨意控制)

操作函數

pthread_mutex_t lock; /* 互斥鎖定義 */
pthread_mutex_init(&lock, NULL); /* 動態初始化，    成功返回0，失敗返回非0 */
pthread_mutex_t thread_mutex = PTHREAD_MUTEX_INITIALIZER； /* 靜態初始化 */
pthread_mutex_lock(&lock); /* 阻塞的鎖定互斥鎖 */
pthread_mutex_trylock(&thread_mutex)；/* 非阻塞的鎖定互斥鎖，成功獲得互斥鎖返回0，如果未能獲得互斥鎖，立即返回一個錯誤碼 */
pthread_mutex_unlock(&lock)； /* 解鎖互斥鎖 */
pthread_mutex_destroy(&lock) /* 銷毀互斥鎖 */

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\n", __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\n", __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\n", __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\n");
        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;
}