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