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// check if write locks are fair
#include <stdio.h>
#include <assert.h>
#include <unistd.h>
#include <pthread.h>
pthread_rwlock_t rwlock;
volatile int killed = 0;
static void *t1_func(void *arg) {
int i;
for (i = 0; !killed; i++) {
int r;
r = pthread_rwlock_wrlock(&rwlock);
assert(r == 0);
usleep(10000);
r = pthread_rwlock_unlock(&rwlock);
assert(r == 0);
}
printf("%lu %d\n", (unsigned long) pthread_self(), i);
return arg;
}
int main(void) {
int r;
#if 0
rwlock = PTHREAD_RWLOCK_INITIALIZER;
#endif
#if 0
pthread_rwlockattr_t attr;
pthread_rwlockattr_init(&attr);
pthread_rwlockattr_setkind_np(&attr, PTHREAD_RWLOCK_PREFER_WRITER_NONRECURSIVE_NP);
r = pthread_rwlock_init(&rwlock, &attr);
#endif
#if 0
pthread_rwlockattr_t attr;
pthread_rwlockattr_init(&attr);
r = pthread_rwlock_init(&rwlock, &attr);
#endif
#if 1
r = pthread_rwlock_init(&rwlock, NULL);
assert(r == 0);
#endif
const int nthreads = 2;
pthread_t tids[nthreads];
for (int i = 0; i < nthreads; i++) {
r = pthread_create(&tids[i], NULL, t1_func, NULL);
assert(r == 0);
}
sleep(10);
killed = 1;
for (int i = 0; i < nthreads; i++) {
void *ret;
r = pthread_join(tids[i], &ret);
assert(r == 0);
}
return 0;
}
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