Question

For debugging I have many calls to a debug log function in my application. Of course in the production version these debugging calls need to be skipped. Instead of writing:

#if DEVEL == 1
    Log::debug(...);
#endif

around all calls to the debug function I decided the write the following in the debug function itself:

#if DEVEL != 1
    return;
#endif

Will the overhead of the useless function call be avoided by the compiler or am I better off by using (many ugly) #if #endif construction for performance reasons?

Answer 1

Instead of worrying about optimizer, you can do a simple trick:

#if DEVEL == 1
#define LOG_DEBUG(...) Log::Debug(__VA_ARGS__)  // variadic macro
#else
#define LOG_DEBUG
#endif

Now use LOG_DEBUG everywhere to keep it simple.