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 …

May 14, 2011 · 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.

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 …

How can I use #if inside #define in the C preprocessor? Asked 15 years, 7 months ago Modified 9 months ago Viewed 51k times

Jan 26, 2012 · How do I define a preprocessor variable through CMake? The equivalent code would be #define foo.

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 …

Mar 4, 2017 · #define simply substitutes a name with its value. Furthermore, a #define 'd constant may be used in the preprocessor: you can use it with #ifdef to do conditional compilation …

Oct 30, 2013 · 8 #define is used to define compile-time constants that you can use with #if to include or exclude bits of code.

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

Feb 12, 2021 · So I read the interesting answers about what are the differences between constexpr and const but I was curious about are the differences between #define and …