RS: NSObject members class and isMemberOfClass
RS: NSObject members class and isMemberOfClass
- Subject: RS: NSObject members class and isMemberOfClass
- From: Roland Silver <email@hidden>
- Date: Fri, 7 Sep 2007 04:51:29 -0600
While attempting to find a way to determine if an object ostensibly
created as an NSMutableArray really is (I can't change it), I wrote
this code:
#import <Cocoa/Cocoa.h>
@interface foo : NSObject {}
@end
@implementation foo
-(void)awakeFromNib {
NSArray* arr = [NSArray array];
NSMutableArray* mut = [NSMutableArray array];
BOOL test1, test2, test3, test4, test5, test6, test7, test8, test9;
test1 = ([arr isMemberOfClass:[NSArray class]]);
test2 = ([mut isMemberOfClass:[NSArray class]]);
test3 = ([arr isMemberOfClass:[NSMutableArray class]]);
test4 = ([mut isMemberOfClass:[NSMutableArray class]]);
test5 = ([mut class] == [NSMutableArray class]);
test6 = ([mut class] == [arr class]);
test7 = ([NSArray class] == [NSArray class]);
test8 = ([NSMutableArray class] == [NSMutableArray class]);
test9 = ([NSArray class] == [NSMutableArray class]);
NSString* arrStr = [arr className];
NSString* mutStr = [mut className];
int mutCount1 = [mut count];
[mut addObject:@"foo"];
int mutCount2 = [mut count];
} //end awakeFromNib
@end
When I run it under debugging with a breakpoint on the right-curly
line, the values of the variables are:
test1 NO
test2 NO
test3 NO
test4 NO
test5 NO
test6 YES
test7 YES
test8 YES
test9 NO
arrStr NSCFArray
mutStr NSCFArray
mutCount1 0
mutCount2 1
which don't make sense to me.
How are the methods <class> and <isMemberOfClass> supposed to work?
How can I determine if an object ostensibly created as an
NSMutableArray really is?
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