Objective C: Method have knowledge of context within which it was called?

Question

I'd like to have a reusable logging method or function that spits out the name of the method it's called from. Example:

    - (void)exampleMethod {
        CustomLog(); //Outputs "exampleMethod"
    }

Duplicate of http://stackoverflow.com/questions/1451342/objective-c-find-caller-of-method ? — David Gelhar, Apr 21 '10 at 02:19
The question is a duplicate (didn't see that and yes I did search), but the answer provided to that question was not useful anyway. Two useful answers have been provided to this question below. Thanks for finding the dupe though. — james_womack, Apr 21 '10 at 02:36

score 2 · Accepted Answer · answered Apr 21 '10 at 02:14

Functions don't know about their calling environment (at least not in a useful way). The only way is to use a macro instead. Inside the macro, you have access to the self and _cmd arguments that hold the receiver and current selector, as well as the __PRETTY_FUNCTION__ macro that contains the human-readable name of the method as a C string.

score 0 · Answer 2 · edited May 23 '17 at 12:13

See How to print out the method name and line number and conditionally disable NSLog? for the inspiration for this answer and other useful NSLog tips. Here is what I desired:

//place in PCH file
#define ILog(fmt, ...) NSLog((@"%s [Line %d] " fmt), __PRETTY_FUNCTION__, __LINE__, ##__VA_ARGS__);

//use in any file in your project
ILog(@"test");// outputs -[AppDelegate applicationDidFinishLaunching:] [Line 38] test

Objective C: Method have knowledge of context within which it was called?

2 Answers2