1 #include <stdio.h>
2 #include <uv.h>
3
4 uv_barrier_t blocker;
5 uv_rwlock_t numlock;
6 int shared_num;
7
reader(void * n)8 void reader(void *n)
9 {
10 int num = *(int *)n;
11 int i;
12 for (i = 0; i < 20; i++) {
13 uv_rwlock_rdlock(&numlock);
14 printf("Reader %d: acquired lock\n", num);
15 printf("Reader %d: shared num = %d\n", num, shared_num);
16 uv_rwlock_rdunlock(&numlock);
17 printf("Reader %d: released lock\n", num);
18 }
19 uv_barrier_wait(&blocker);
20 }
21
writer(void * n)22 void writer(void *n)
23 {
24 int num = *(int *)n;
25 int i;
26 for (i = 0; i < 20; i++) {
27 uv_rwlock_wrlock(&numlock);
28 printf("Writer %d: acquired lock\n", num);
29 shared_num++;
30 printf("Writer %d: incremented shared num = %d\n", num, shared_num);
31 uv_rwlock_wrunlock(&numlock);
32 printf("Writer %d: released lock\n", num);
33 }
34 uv_barrier_wait(&blocker);
35 }
36
main()37 int main()
38 {
39 uv_barrier_init(&blocker, 4);
40
41 shared_num = 0;
42 uv_rwlock_init(&numlock);
43
44 uv_thread_t threads[3];
45
46 int thread_nums[] = {1, 2, 1};
47 uv_thread_create(&threads[0], reader, &thread_nums[0]);
48 uv_thread_create(&threads[1], reader, &thread_nums[1]);
49
50 uv_thread_create(&threads[2], writer, &thread_nums[2]);
51
52 uv_barrier_wait(&blocker);
53 uv_barrier_destroy(&blocker);
54
55 uv_rwlock_destroy(&numlock);
56 return 0;
57 }
58
