多线程使用互斥锁的C范例

#include <stdio.h>
#include <sys/time.h>
#include <pthread.h>

int pThreadActVarMagPCID = -1;
pthread_t pThreadActVarMagPC;
pthread_mutex_t BACK_COMM_mutex = PTHREAD_MUTEX_INITIALIZER ;

void *ActVarMagThread(void *pdbdata)
{
    printf("--------------------\n");
        printf(" actvarmagthread on \n");
        printf("--------------------\n");
    while(1)
    {
         if(pthread_mutex_lock(&BACK_COMM_mutex)!=0)
        {
                    printf("ActVarMagThread BACK_COMM_mutex lock err !!\n");
            break;
        }
        usleep(40);
        if(pthread_mutex_unlock(&BACK_COMM_mutex)!=0) //unlock
                {
            printf("ActVarMagThread pthread_mutex_unlock err !!\n");
            break;
        }
        usleep(100);
    }
    sleep(1);
}

int main(void)
{
    printf("mul thread starting test \n");
    pthread_mutex_init(&BACK_COMM_mutex,NULL); 
    memset((void *)&pThreadActVarMagPC, 0, sizeof(pThreadActVarMagPC));
    if((pThreadActVarMagPCID = pthread_create(&pThreadActVarMagPC, NULL, ActVarMagThread, NULL)) != 0) 
    {
        printf("ActVarMagPC fork err !!");
        return -1;   
    }
    else
    {
        while(1)
        {
             if(pthread_mutex_lock(&BACK_COMM_mutex)!=0)
            {
                        printf("BACK_COMM_mutex lock err !!\n");
                break;
            }
            usleep(40);
            if(pthread_mutex_unlock(&BACK_COMM_mutex)!=0) //unlock
                    {
                printf("pthread_mutex_unlock err \n");
                break;
            }
            usleep(100);
        }
    }
    sleep(1);
    return 0;
}