ErlDrvRWLock *
erl_drv_rwlock_create(char *name)
{
#ifdef USE_THREADS
ErlDrvRWLock *drwlck = erts_alloc_fnf(ERTS_ALC_T_DRV_RWLCK,
(sizeof(ErlDrvRWLock)
+ (name ? sys_strlen(name) + 1 : 0)));
if (drwlck) {
if (ethr_rwmutex_init(&drwlck->rwmtx) != 0) {
erts_free(ERTS_ALC_T_DRV_RWLCK, (void *) drwlck);
drwlck = NULL;
}
else if (!name)
drwlck->name = no_name;
else {
drwlck->name = ((char *) drwlck) + sizeof(ErlDrvRWLock);
sys_strcpy(drwlck->name, name);
}
}
return drwlck;
#else
return (ErlDrvRWLock *) NULL;
#endif
}
static void
rwmutex_test(void)
{
int data;
int res;
ethr_tid tid;
print_line("Trying to initialize rwmutex");
res = ethr_rwmutex_init(&rwmt_rwmutex);
ASSERT(res == 0);
print_line("Initialized rwmutex");
rwmt_data = 4711;
print_line("Main thread tries to read lock rwmutex");
ethr_rwmutex_rlock(&rwmt_rwmutex);
print_line("Main thread read locked rwmutex");
ASSERT(rwmt_data == 4711);
print_line("Main thread about to create aux thread");
res = ethr_thr_create(&tid, rwmt_thread, NULL, NULL);
ASSERT(res == 0);
print_line("Main thread created aux thread");
print_line("Main thread goes to sleep for 1 second");
do_sleep(1);
print_line("Main thread woke up");
ASSERT(rwmt_data == 4711);
print_line("Main thread tries to read unlock rwmutex");
ethr_rwmutex_runlock(&rwmt_rwmutex);
print_line("Main thread read unlocked rwmutex");
print_line("Main thread tries to write lock rwmutex");
ethr_rwmutex_rwlock(&rwmt_rwmutex);
print_line("Main thread write locked rwmutex");
data = ++rwmt_data;
print_line("Main thread goes to sleep for 1 second");
do_sleep(1);
print_line("Main thread woke up");
ASSERT(rwmt_data == data);
++rwmt_data;
print_line("Main thread tries to write unlock rwmutex");
ethr_rwmutex_rwunlock(&rwmt_rwmutex);
print_line("Main thread write unlocked rwmutex");
res = ethr_thr_join(tid, NULL);
ASSERT(res == 0);
print_line("Main thread joined aux thread");
res = ethr_rwmutex_destroy(&rwmt_rwmutex);
ASSERT(res == 0);
print_line("Main thread destroyed rwmutex");
}
