C preprocessor snippets: Difference between revisions
Jump to navigation
Jump to search
Content added Content deleted
(move to category) Tag: New redirect |
|||
| Line 1: | Line 1: | ||
#REDIRECT [[Category:C preprocessor snippets]] |
|||
=== Check if a macro is set to 1 === |
|||
This works both in <code>#if</code> preprocessor expressions and in actual C code: |
|||
<source lang="C"> |
|||
// https://stackoverflow.com/a/10119699/1697183 |
|||
// https://news.ycombinator.com/item?id=3830609 |
|||
// https://github.com/torvalds/linux/commit/69349c2dc01c489eccaa4c472542c08e370c6d7e |
|||
#define is_set(macro) is_set_(macro) |
|||
#define macrotest_1 , |
|||
#define is_set_(value) is_set__(macrotest_##value) |
|||
#define is_set__(comma) is_set___(comma 1, 0) |
|||
#define is_set___(_, v, ...) v |
|||
</source> |
|||
=== See also === |
|||
* [[Range-based for loop]] |
|||
* [[incbin()]] |
|||
* [[__is_constexpr()]] |
|||
* [[X macros]] |
|||
[[Category:Programming]] |
|||
[[Category:C]] |
|||
Latest revision as of 11:58, 1 March 2020
Redirect to: