brainbaking/content/wiki/code/c/preprocessing.md

+++ title = "preprocessing" draft = false tags = [ "", "Users", "jefklak", "Downloads", "pages", "code", "c", "preprocessing" ] date = "2013-12-02" +++

Preprocessing

Handige macro's

Exception/Debug informatie expanden

#define _ERROR_STR2(a) #a
#define _ERROR_STR(a) _ERROR_STR2(a)
#define ERROR_INFO(fn) _T(_ERROR_STR(__FILE__" line: "__LINE__" function: "fn))

Te gebruiken als someFn(ERROR_INFO("bla")). Merk op dat __FUNCTION__ of __FUNC__ ook gebruikt kan worden, afhankelijk van de C++ compiler, maar dit is geen deel van de standaard (vanaf C++ v11).

De #a notatie wordt gebruikt om iets te stringifyen in de preprocessor, vandaar de delegate:

Sometimes you may want to convert a macro argument into a string constant. Parameters are not replaced inside string constants, but you can use the ‘#’ preprocessing operator instead. When a macro parameter is used with a leading ‘#’, the preprocessor replaces it with the literal text of the actual argument, converted to a string constant. Unlike normal parameter replacement, the argument is not macro-expanded first. This is called stringification.