Objective-c disable function with conditional macros - objective-c

Question

I have a custom logging function that i would like to disable for realease builds. But the problem is it only lets me to replace that function with another empty one. Here's what i would like to do:
#ifdef SMTH
#define logfunction(...)
#else
void logfunction(NSString *fmt, ...) { some logging code goes here }
#endif
To make this work, i could replace the function with a macro, including VA_ARGS and such, but ... the problem is that my xCode loses code completion inside the braces of logfunction(). Now if the logging facility is defined as a function - code completion works fine.
The only solution i have so far is this:
#ifdef SMTH
void logfunction(NSString *fmt, ...) { /* no code here */ }
#else
void logfunction(NSString *fmt, ...) { some logging code goes here }
#endif
This works fine, but there is a call to an empty function in release builds. Is there any way to work around this?
UPDATE - my bad - everything works
The first example actually works, i simply forgot to do the same conditional macro in the ".h" file ...

Answer 1

I think that your current solution is already good enough. The empty function wont cause much trouble (in terms of wasting much time when it is called). Probably the compiler will even remove the call to the empty function altogether.
However, if you still want to get rid of it, you can try what I am doing:
Wrap your log function into a macro, and define that macro conditionally.
Example:
#ifdef SMTH
#define logfunction(fmt, ...)
#else
#define logfunction(fmt, ...) __logfunction((fmt), ##__VA_ARGS__)
#endif
where __logfunction(NSString *fmt, ...) is your actual logging function. This will completely remove the call to the function, when your SMTH is set.
By the way, you may want to use the DEBUG flag, that is set per default in XCode for non-release builds (see the "Preprocessor Macros" setting in your target in XCode). You would need to switch the cases around inside the #ifdef, obviously, or make it a #ifndef DEBUG.