Trick « preprocessor « C Q&A

1. wonder about some #define tricks    stackoverflow.com

Whlie reading codes of my group project, I come across many DEFINEs, and some of them seems strange. To generalize it, please look at the following 2 examples. Example 1: ...

2. Type-generic programming with macros: tricks to determine type?    stackoverflow.com

It's possible to do certain types of type-generic-functions as macros in C, for instance things like:

#define SQRT(x) (sizeof(x) == sizeof(float) ? sqrtf((x)) : \
        ...

3. Preprocessor trick    bytes.com

Hi All, I'm trying to define a macro that will allow me to write the following code : #include MY_MACRO( NAME, SPACE ) and end up with the following preprocessed code : #include NAME.hpp namespace SPACE { typedef NAME ImportedNAME; } I have a macro that generates the correct text but since macros expand on one unique line, what I actually ...

4. Preprocessor trick    forums.devshed.com

Your examples do not appear to be very useful, but perhaps you left out some context? The ## operator is referred to as the token pasting operator. It can be useful for a number of things when writing macros. It basically pastes the operands on either side of it together. Here's one useful example if you do much Windows programming: Code: ...