Question

I have a library that has several options defined as this:

#define shouldShowToolbar YES
#define shouldAlignToLeft YES
etc..

and I’m looking for a way to actually replace those from outside (without modifying the library, because the future updates will break it). Is it possible, or am I doomed to change the library source code (which I do have) every time an update comes out.

Answer 1

There is #undef

#include "library_header.h"    /* Which defines the macro.  */

#undef shouldShowToolbar       /* You undef it.  */
#define shouldShowToolbar NO   /* If you want, you can redefine it.  */

http://gcc.gnu.org/onlinedocs/cpp/Undefining-and-Redefining-Macros.html