线程间通讯《代码》pthread_cond_t

1. #define _GNU_SOURCE
2. #include <unistd.h>
3. #include <pthread.h>
4.  
5. #include <stdlib.h>
6. #include <stdio.h>
7.  
8. //static pthread_rwlock_t rwlock = PTHREAD_RWLOCK_INITIALIZER;
9. // 这里虽然是 P/V ，但是用 cond 确实更方便。
10. static pthread_cond_t cond = PTHREAD_COND_INITIALIZER;
11. static pthread_mutex_t mutex = PTHREAD_MUTEX_INITIALIZER;
12.  
13. int i = 0;
14.  
15. void get ( )
16. {
17. pthread_mutex_lock (&mutex );
18. while ( i == 0 ) // 队列下限
19. pthread_cond_wait (&cond, &mutex ); // 唤醒其它线程进行检测。
20.  
21. --i;
22. pthread_cond_signal (&cond );
23. printf ( "Current size: %d\n", i );
24.  
25. pthread_mutex_unlock (&mutex );
26. }
27.  
28. void put ( )
29. {
30. pthread_mutex_lock (&mutex );
31. while ( i == 3 ) // 队列上限
32. pthread_cond_wait (&cond, &mutex );
33.  
34. ++i;
35. pthread_cond_signal (&cond ); // 唤醒其它线程
36. printf ( "Now size: %d\n", i );
37.  
38. pthread_mutex_unlock (&mutex );
39. }
40.  
41. void *thf ( void *arg )
42. {
43. while ( 1 )
44. {
45. put ( );
46. }
47. }
48.  
49. int main ( )
50. {
51. pthread_t tid;
52. pthread_create (&tid, NULL, thf, NULL );
53.  
54. sleep ( 3 );
55. while ( 1 )
56. get ( );
57. }