Calling a method on an unitialized object (null pointer)
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by Florin
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Published on 2010-04-23T07:29:42Z
Indexed on
2010/04/23
7:33 UTC
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- What is the normal behavior in Objective-C if you call a method on an object (pointer) that is nil (maybe because someone forgot to initialize it)? Shouldn't it generate some kind of an error (segmentation fault, null pointer exception...)?
- If this is normal behavior, is there a way of changing this behavior (by configuring the compiler) so that the program raises some kind of error / exception at runtime?
To make it more clear what I am talking about, here's an example.
Having this class:
@interface Person : NSObject {
NSString *name;
}
@property (nonatomic, retain) NSString *name;
- (void)sayHi;
@end
with this implementation:
@implementation Person
@synthesize name;
- (void)dealloc {
[name release];
[super dealloc];
}
- (void)sayHi {
NSLog(@"Hello");
NSLog(@"My name is %@.", name);
}
@end
Somewhere in the program I do this:
Person *person = nil;
//person = [[Person alloc] init]; // let's say I comment this line
person.name = @"Mike"; // shouldn't I get an error here?
[person sayHi]; // and here
[person release]; // and here
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