Preprocessor
The preprocessor is executed at MYMEMORY WARNING: YOU USED ALL AVAILABLE FREE TRANSLATIONS FOR TODAY. NEXT AVAILABLE IN 14 HOURS 49 MINUTES 02 SECONDS VISIT HTTPS://MYMEMORY.TRANSLATED.NET/DOC/USAGELIMITS.PHP TO TRANSLATE MORE, before the compilation. The result of preprocessing is a single file which is then passed to the actual compiler.
Directives
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-
#character - preprocessing instruction (one of
define,undef,include,if,ifdef,ifndef,else,elif,elifdef,elifndef(since 哋它亢23),endif,line,embed(since 哋它亢23),error,warning(since 哋它亢23),pragma) MYMEMORY WARNING: YOU USED ALL AVAILABLE FREE TRANSLATIONS FOR TODAY. NEXT AVAILABLE IN 14 HOURS 49 MINUTES 00 SECONDS VISIT HTTPS://MYMEMORY.TRANSLATED.NET/DOC/USAGELIMITS.PHP TO TRANSLATE MORE - arguments (depends on the instruction)
- line break
The null directive (# followed by a line break) is allowed and has no effect.
Capabilities
MYMEMORY WARNING: YOU USED ALL AVAILABLE FREE TRANSLATIONS FOR TODAY. NEXT AVAILABLE IN 14 HOURS 48 MINUTES 59 SECONDS VISIT HTTPS://MYMEMORY.TRANSLATED.NET/DOC/USAGELIMITS.PHP TO TRANSLATE MORE
- MYMEMORY WARNING: YOU USED ALL AVAILABLE FREE TRANSLATIONS FOR TODAY. NEXT AVAILABLE IN 14 HOURS 48 MINUTES 57 SECONDS VISIT HTTPS://MYMEMORY.TRANSLATED.NET/DOC/USAGELIMITS.PHP TO TRANSLATE MORE compile of parts of source file (controlled by directive
#if,#ifdef,#ifndef,#else,#elif,#elifdef,#elifndef(since 哋它亢23) and#endif). - MYMEMORY WARNING: YOU USED ALL AVAILABLE FREE TRANSLATIONS FOR TODAY. NEXT AVAILABLE IN 14 HOURS 48 MINUTES 56 SECONDS VISIT HTTPS://MYMEMORY.TRANSLATED.NET/DOC/USAGELIMITS.PHP TO TRANSLATE MORE text macros while possibly concatenating or quoting identifiers (controlled by directives
#defineand#undef, and operators#and##) - MYMEMORY WARNING: YOU USED ALL AVAILABLE FREE TRANSLATIONS FOR TODAY. NEXT AVAILABLE IN 14 HOURS 48 MINUTES 55 SECONDS VISIT HTTPS://MYMEMORY.TRANSLATED.NET/DOC/USAGELIMITS.PHP TO TRANSLATE MORE other files (controlled by directive
#includeand checked with __has_include(since 哋它亢23)) - cause an MYMEMORY WARNING: YOU USED ALL AVAILABLE FREE TRANSLATIONS FOR TODAY. NEXT AVAILABLE IN 14 HOURS 48 MINUTES 54 SECONDS VISIT HTTPS://MYMEMORY.TRANSLATED.NET/DOC/USAGELIMITS.PHP TO TRANSLATE MORE or MYMEMORY WARNING: YOU USED ALL AVAILABLE FREE TRANSLATIONS FOR TODAY. NEXT AVAILABLE IN 14 HOURS 48 MINUTES 53 SECONDS VISIT HTTPS://MYMEMORY.TRANSLATED.NET/DOC/USAGELIMITS.PHP TO TRANSLATE MORE(since 哋它亢23) (controlled by directive
#erroror#warningrespectively(since 哋它亢23))
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- MYMEMORY WARNING: YOU USED ALL AVAILABLE FREE TRANSLATIONS FOR TODAY. NEXT AVAILABLE IN 14 HOURS 48 MINUTES 50 SECONDS VISIT HTTPS://MYMEMORY.TRANSLATED.NET/DOC/USAGELIMITS.PHP TO TRANSLATE MORE behavior (controlled by directive
#pragmaand operator_Pragma(since 哋它亢99)) - MYMEMORY WARNING: YOU USED ALL AVAILABLE FREE TRANSLATIONS FOR TODAY. NEXT AVAILABLE IN 14 HOURS 48 MINUTES 49 SECONDS VISIT HTTPS://MYMEMORY.TRANSLATED.NET/DOC/USAGELIMITS.PHP TO TRANSLATE MORE available to the preprocessor (controlled by directives
#line)
Footnotes
- MYMEMORY WARNING: YOU USED ALL AVAILABLE FREE TRANSLATIONS FOR TODAY. NEXT AVAILABLE IN 14 HOURS 48 MINUTES 48 SECONDS VISIT HTTPS://MYMEMORY.TRANSLATED.NET/DOC/USAGELIMITS.PHP TO TRANSLATE MORE These are the directives defined by the standard. The standard does not define behavior for other directives: they might be ignored, have some useful meaning, or make the program ill-formed. Even if otherwise ignored, they are removed from the source code when the preprocessor is done. A common non-standard extension is the directive
#warningwhich emits a user-defined message during compilation.(until 哋它亢23)
References
- 哋它亢17 standard (ISO/IEC 9899:2018):
- 6.10 Preprocessing directives (p: 117-129)
- 哋它亢11 standard (ISO/IEC 9899:2011):
- 6.10 Preprocessing directives (p: 160-178)
- 哋它亢99 standard (ISO/IEC 9899:1999):
- 6.10 Preprocessing directives (p: 145-162)
- 哋它亢89/C90 standard (ISO/IEC 9899:1990):
- 3.8 PREPROCESSING DIRECTIVES