基于信号量与互斥锁实现的生产者和消费者

• 信号量API

  •  #include <semaphore.h>
    2 //等待互斥量（原子操作)
    3 int sem_wait(sem_t *serm);
    4 //通知互斥量加一
    5 int sem_post(sem_t *sem);

• 　基于信号量与互斥锁实现的生产者和消费者

  •   1 #include <stdio.h>
      2 #include <stdlib.h>
      3 #include <unistd.h>
      4 #include <sys/types.h>
      5 #include <pthread.h>
      6 #include <errno.h>
      7 #include <string.h>
      8 #include <semaphore.h>
      9 
     10 #define ERR_EXIT(m)\
     11     do\
     12     {\
     13         perror(m);\
     14         exit(EXIT_FAILURE);\
     15     }while(0)\
     16 
     17 #define CONSUMER_COUNT 1
     18 #define PRODUCE_COUNT 2
     19 
     20 #define BUFFSIZE 10
     21 int g_buffer[BUFFSIZE];
     22 
     23 unsigned short in = 0;
     24 unsigned short out = 0;
     25 unsigned short produce_id = 0;
     26 unsigned short consume_id = 0;
     27 
     28 sem_t g_sem_full;
     29 sem_t g_sem_empty;
     30 
     31 pthread_mutex_t g_mutex;
     32 
     33 pthread_t g_thread[CONSUMER_COUNT+PRODUCE_COUNT];
     34 
     35 void* consume(void* arg)
     36 {
     37     int num= (int*)arg;
     38     int i;
     39     while(1)
     40     {
     41         printf("%d wait buffer not  empty\n",num);
     42         sem_wait(&g_sem_empty);
     43         pthread_mutex_lock(&g_mutex);
     44     
     45         for(i = 0; i< BUFFSIZE; i++)
     46         {
     47             printf("%02d ",i);
     48             if(g_buffer[i] == -1)
     49                 printf("%s","null");
     50             else
     51                 printf("%d",g_buffer[i]);
     52             if(i == out)
     53                 printf("\t<--consume");
     54             printf("\n");
     55         }
     56 
     57         consume_id = g_buffer[out];
     58         printf("%d begin consume product %d\n",num, consume_id);
     59         g_buffer[out] = -1;
     60         out = (out +  1)%BUFFSIZE;
     61         printf("%d end consume produce %d\n",num,consume_id); 
     62 
     63         pthread_mutex_unlock(&g_mutex);
     64         sem_post(&g_sem_full);
     65         sleep(1);
     66     }
     67     return NULL;
     68 }
     69 
     70 void* produce(void* arg)
     71 {
     72     int num = (int*)arg;
     73     int i;
     74     while(1)
     75     {
     76         printf("%d wait buffer not full\n",num);
     77         sem_wait(&g_sem_full);
     78         pthread_mutex_lock(&g_mutex);
     79     
     80         for(i = 0; i< BUFFSIZE; i++)
     81         {
     82             printf("%02d ",i);
     83             if(g_buffer[i] == -1)
     84                 printf("%s","null");
     85             else
     86                 printf("%d",g_buffer[i]);
     87             if(i == in)
     88                 printf("\t<--produce");
     89             printf("\n");
     90         }
     91 
     92         printf("%d begin produce product %d\n",num, produce_id);
     93         g_buffer[in] = produce_id;
     94         in = (in +  1)%BUFFSIZE;
     95         printf("%d end produce produce %d\n",num,produce_id++); 
     96         
     97         pthread_mutex_unlock(&g_mutex);
     98         sem_post(&g_sem_empty);
     99         sleep(1);
    100     }
    101     return NULL;
    102 }
    103 
    104 int main(void)
    105 {
    106     int i;
    107     for(i = 0; i < BUFFSIZE;i++)
    108         g_buffer[i] = -1;
    109     sem_init(&g_sem_full, 0, BUFFSIZE);
    110     sem_init(&g_sem_empty, 0, 0);
    111 
    112     pthread_mutex_init(&g_mutex,NULL);
    113 
    114     for(i = 0; i< CONSUMER_COUNT; i++)
    115     {
    116         pthread_create(&g_thread[i], NULL,consume, (void*)i);
    117     }
    118 
    119     for(i = 0; i< PRODUCE_COUNT; i++)
    120     {
    121         pthread_create(&g_thread[i], NULL,produce, (void*)i);
    122     }
    123 
    124     for(i = 0; i < CONSUMER_COUNT + PRODUCE_COUNT; i++)
    125     {
    126         pthread_join(g_thread[i],NULL);    
    127     }
    128 
    129 
    130     pthread_mutex_destroy(&g_mutex);
    131     sem_destroy(&g_sem_full);
    132     sem_destroy(&g_sem_empty);
    133 
    134 
    135     return 0;
    136 }