Question

I have a special NSLog method swizzle that prints the current method as part of the log statement.

For Objective-C methods, I have a macro that uses: NSStringFromSelector(_cmd)

For non Objective-C methods, I have a second macro that uses __PRETTY_FUNCTION__ because _cmd is not defined.

I am now trying to use the same macro for both, so I am trying to test if it is defined and thought I could do so like this:

NSString *command = (&_cmd != nil ? NSStringFromSelector(_cmd) : [NSString stringWithCString:__PRETTY_FUNCTION__ encoding:NSUTF8StringEncoding])

but I am still getting some Use of undeclared identifier '_cmd' errors when the macro is used in non Objective-C methods. How can I do a runtime test do determine if _cmd is defined or not?

Answer 1

You cannot test at runtime whether _cmd is defined.

The __PRETTY_FUNCTION__ macro is defined in Objective-C methods. Just use __PRETTY_FUNCTION__ everywhere and don’t try to use _cmd.

Example:

- (IBAction)mapWasTapped:(UITapGestureRecognizer *)sender {
    NSLog(@"%s", __PRETTY_FUNCTION__);
}

Here’s the output:

2012-12-01 11:45:30.036 TestApp[92581:c07] -[MainViewController mapWasTapped:]