2011年5月14日 · What is the point of #define in C++? I've only seen examples where it's used in place of a "magic number" but I don't see the point in just giving that value to a variable instead.

The question is if users can define new macros in a macro, not if they can use macros in macros.

I want to write a macro that spits out code based on the Boolean value of its parameter. So say DEF_CONST(true) should be expanded into const, and DEF_CONST(false) should be expanded …

In other words, when the compiler starts building your code, no #define statements or anything like that is left. A good way to understand what the preprocessor does to your code is to get hold of the …

As far as I know, what you're trying to do (use if statement and then return a value from a macro) isn't possible in ISO C... but it is somewhat possible with statement expressions (GNU extension). Since …

2010年8月24日 · Macros (created with #define) are always replaced as written, and can have double-evaluation problems. inline on the other hand, is purely advisory - the compiler is free to ignore it. …

The #define directive is a preprocessor directive; the preprocessor replaces those macros by their body before the compiler even sees it. Think of it as an automatic search and replace of your source code. …

2012年6月18日 · #define WIDTH 10 is a preprocessor directive that allows you to specify a name (WIDTH) and its replacement text (10). The preprocessor parses the source file and each occurrence …

2009年11月4日 · Which one is better to use among the below statements in C? static const int var = 5; or #define var 5 or enum { var = 5 };

2009年10月28日 · Is it better to use static const variables than #define preprocessor? Or does it maybe depend on the context? What are advantages/disadvantages for each method?