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Lam
Lam

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C Preprocessor cheatsheet

#cpreprocessor #cheatsheet

The C preprocessor is the macro preprocessor for the C, Objective-C, and C++ computer programming languages. The preprocessor provides the ability for the inclusion of header files, macro expansions, conditional compilation, and line control. C Preprocessor Cheat Sheet is quick reference for the C macro preprocessor, which can be used independently of C/C++.

File and line 

#define LOG(msg) console.log(__FILE__, __LINE__, msg)
#=> console.log("file.txt", 3, "hey")
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Stringification 

#define STR(name) #name
char * a = STR(object);   #=> char * a = "object";
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Token concat 

#define DST(name) name##_s name##_t
DST(object);   #=> object_s object_t;
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Macro 

#define DEG(x) ((x) * 57.29)
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Error 

#if VERSION == 2.0
  #error Unsupported
  #warning Not really supported
#endif
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[Reference] If 

#ifdef DEBUG
  console.log('hi');
#elif defined VERBOSE
  ...
#else
  ...
#endif
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Defines 

#define FOO
#define FOO "hello"

#undef FOO
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Includes 

#include "file"
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Compiling 

$ cpp -P file > outfile
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Reference

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