互斥锁线程控制

、pthread_mutex_init
函数的作用：初始化互斥锁
函数的原型：int pthread_mutex_init(pthread_mutex_t *restrict,const pthread_mutexattr_t *mutexattr)
函数的参数：mutex：互斥锁
                   mutexattr：PTHREAD_MUTEX_INITIALIZER：快速互斥锁
返回值：成功0；出错：-1
2、pthread_mutex_lock
函数的作用：对互斥锁上锁，判断，解除，破坏锁
函数的原型：pthread_mutex_lock（pthread_mutex_t *mutex）
pthread_mutex_trylock（pthread_mutex_t *mutex）
pthread_mutex_unlock（pthread_mutex_t *mutex）
pthread_mutex_destroy（pthread_mutex_t *mutex）
函数实现代码：
#include
#include
#include




#define  THREAD_NUM  3
#define  REPEAT_NUM  3
#define  DELAY_TIME_LEVELS  6.0  




pthread_mutex_t mutex;




void *thrd_func(void *arg)
{
    int thrd_num = (int)arg;
    int delay_time =0, count=0;
    int res;
    
    res = pthread_mutex_lock(&mutex);
    if(res)
    {
    printf("Thread %d  lock failed\n", thrd_num);
    pthread_exit(NULL);
    }
    printf("Thread %d is starting\n", thrd_num);
    for(count=0; count     {
        delay_time=(int)(rand()*DELAY_TIME_LEVELS/(RAND_MAX))+1;
        sleep(delay_time);
        printf("\tThread %d:job %d delay=%d\n", thrd_num,count, delay_time);
    }
    printf("Thread %d finish\n", thrd_num);
    pthread_mutex_unlock(&mutex);
    pthread_exit(NULL);
}








int main(void)
{
   pthread_t thread[THREAD_NUM];
   int no=0, res;
   void *thrd_ret;
   
   srand(time(NULL));
   pthread_mutex_init(&mutex, NULL);
   
   for(no=0; no    {
       res=pthread_create(&thread[no], NULL, thrd_func, (void *)no);
       if(res !=0 )
       {
           printf("create thread %d failed\n", no);
           exit(res);
       }
   }
   printf("creatr threads success\nwaiting for threads to finish....\n");
   for(no=0; no    {
      res=pthread_join(thread[no], &thrd_ret);
      if(!res)
      {
          printf("thread  %d joined\n", no);
      }
      else
      {
           printf("thread  %d failed\n", no);
      }
   }
   pthread_mutex_destroy(&mutex);
   return 0;
}




#include
#include
#include  
int myglobal=0;




pthread_mutex_t mymutex=PTHREAD_MUTEX_INITIALIZER;




void *thread_function(void *arg) 
{
  int i,j;
  
  for ( i=0; i<20; i++)
  {
    pthread_mutex_lock(&mymutex);
    myglobal=myglobal+1;
    printf(".");
    fflush(stdout);
    sleep(1);
    pthread_mutex_unlock(&mymutex);
  }
  return NULL;
}




int main(void) 
{
  pthread_t mythread;
  int i;
  
  if ( pthread_create( &mythread, NULL, thread_function, NULL) ) 
  {
    printf("error creating thread.");
    pthread_exit(0);
  }
  
  for ( i=0; i<20; i++) 
  {
    pthread_mutex_lock(&mymutex);
    myglobal=myglobal+1;
    pthread_mutex_unlock(&mymutex);
    printf("o");
    fflush(stdout);
    sleep(1);
  }
  
  if ( pthread_join ( mythread, NULL ) ) 
  {
     printf("error joining thread.");
     pthread_exit(0);
  }
  
  printf("\nmyglobal equals %d\n",myglobal);
  exit(0);
}