Листинг 8.6. Функция pthread_rwlock_wrlock: получение блокировки на запись
//my_rwlock/pthread_rwlock_wrlock.c
1 #include "unpipc.h"
2 #include "pthread_rwlock.h"
3 int
4 pthread_rwlock_wrlock(pthread_rwlock_t *rw)
5 {
6 int result;
7 if (rw->rw_magic != RW_MAGIC)
8 return(EINVAL);
9 if ((result = pthread_mutex_lock(&rw->rw_mutex)) != 0)
10 return(result);
11 while (rw->rw_refcount != 0) {
12 rw->rw_nwaitwriters++;
13 result = pthread_cond_wait(&rw->rw_condwriters, &rw->rw_mutex);
14 rw->rw_nwaitwriters--;
15 if (result != 0)
16 break;
17 }
18 if (result == 0)
19 rw->rw_refcount = –1;
20 pthread_mutex_unlock(&rw->rw_mutex);
21 return(result);
22 }