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타이머에 대한 cancel_handler가있는 경우 'assign'속성을 사용하여 속성으로 선언 된 ivars를 직접 참조하고 재설정 할 수 있습니까? 아니면 먼저 __block으로 할당해야합니까?dispatch_source_set_cancel_handler 및 @property ivar에 nil 할당
@interface SomeClass: NSObject { }
@property (nonatomic, assign) dispatch_source_t timer;
@end
// Class implementation
@implementation SomeClass
@synthesize timer = _timer;
- (void)startTimer
{
dispatch_queue_t globalQ = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0);
self.timer = dispatch_source_create(DISPATCH_SOURCE_TYPE_TIMER,
0, 0, globalQ);
dispatch_time_t startWhen = dispatch_walltime(DISPATCH_TIME_NOW, NSEC_PER_SEC * 1);
dispatch_source_set_timer(_timer, startWhen, 1 * NSEC_PER_SEC, 5000ull);
dispatch_source_set_event_handler(_timer, ^{
// timer's event handler
});
// VERSION 1:
// Is it okay to reference and assign self.timer to nil
// or does it have to be declared as __block as in VERSION 2?
dispatch_source_set_cancel_handler(_timer, ^{
dispatch_release(_timer);
self.timer = nil;
});
// VERSION 2:
__block myTimer = self.timer;
dispatch_source_set_cancel_handler(_timer, ^{
dispatch_release(myTimer);
myTimer = nil;
});
dispatch_resume(_timer);
}