performSelector ARC warning [duplicate] - objective-c

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Closed 10 years ago.
Possible Duplicate:
performSelector may cause a leak because its selector is unknown
I have this code in non-ARC that works without errors or warnings:
- (void)addTarget:(id)target action:(SEL)action forControlEvents:(UIControlEvents)controlEvents
{
// Only care about value changed controlEvent
_target = target;
_action = action;
}
- (void)setValue:(float)value
{
if (value > _maximumValue)
{
value = _maximumValue;
} else if (value < _minimumValue){
value = _minimumValue;
}
// Check range
if (value <= _maximumValue & value >= _minimumValue)
{
_value = value;
// Rotate knob to proper angle
rotation = [self calculateAngleForValue:_value];
// Rotate image
thumbImageView.transform = CGAffineTransformMakeRotation(rotation);
}
if (continuous)
{
[_target performSelector:_action withObject:self]; //warning here
}
}
However, after I convert to project to ARC, I get this warning:
"Perform Selector may cause a leak because its selector is unknown."
I would appreciate ideas on how to revise my code accordingly..

Answer 1

The only way I've found to avoid the warning is to suppress it. You could disable it in your build settings, but I prefer to just use pragmas to disable it where I know it's spurious.
# pragma clang diagnostic push
# pragma clang diagnostic ignored "-Warc-performSelector-leaks"
[_target performSelector:_action withObject:self];
# pragma clang diagnostic pop
If you're getting the error in several places, you can define a macro to make it easier to suppress the warning:
#define SuppressPerformSelectorLeakWarning(Stuff) \
do { \
_Pragma("clang diagnostic push") \
_Pragma("clang diagnostic ignored \"-Warc-performSelector-leaks\"") \
Stuff; \
_Pragma("clang diagnostic pop") \
} while (0)
You can use the macro like this:
SuppressPerformSelectorLeakWarning([_target performSelector:_action withObject:self]);