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  1. #define CAT(a, ...) PRIMITIVE_CAT(a, __VA_ARGS__)
  2. #define PRIMITIVE_CAT(a, ...) a ## __VA_ARGS__
  3.  
  4. #define IIF(c) PRIMITIVE_CAT(IIF_, c)
  5. #define IIF_0(t, ...) __VA_ARGS__
  6. #define IIF_1(t, ...) t
  7.  
  8. #define PROBE(x) x, 1 
  9.  
  10. #define CHECK(...) CHECK_N(__VA_ARGS__, 0)
  11. #define CHECK_N(x, n, ...) n
  12.  
  13. #define ENABLE_USER_gwiazdorrr () // gwiazdorrr is now enabled
  14. #define ENABLE_USER_foo ()        // foo is also enabled
  15. // #define ENABLE_USER_bar ()     // bar is NOT enabled
  16.  
  17. #define USER_ENABLED_PROBE(user)            USER_ENABLED_PROBE_PROXY( ENABLE_USER_##user ) // concatenate prefix with user name
  18. #define USER_ENABLED_PROBE_PROXY(...)       USER_ENABLED_PROBE_PRIMIVIE(__VA_ARGS__)       // expand arguments
  19. #define USER_ENABLED_PROBE_PRIMIVIE(x)      USER_ENABLED_PROBE_COMBINE_ x                  // merge
  20. #define USER_ENABLED_PROBE_COMBINE_(...)    PROBE(~)                                       // if merge successful, expand to probe
  21.  
  22. #define IS_USER_ENABLED(user) CHECK(USER_ENABLED_PROBE(user))
  23.  
  24.  
  25. #define TURN_OPTIMISATION_OFF(user) IIF( IS_USER_ENABLED(user) ) \
  26.     (\
  27.         _Pragma ("GCC optimize \"0\""),\
  28.         /* nothing */ \
  29.     )
  30.  
  31. TURN_OPTIMISATION_OFF(gwiazdorrr) // expands into __pragma optimize("", off)
  32. TURN_OPTIMISATION_OFF(foo)        // expands into __pragma optimize("", off)
  33. TURN_OPTIMISATION_OFF(bar)        // nothing emitted
  34.  
  35. int main()
  36. {
  37. 	return 0;
  38. }
Success #stdin #stdout 0.02s 2720KB
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https://ideone.com/129eo
language:
C++ (gcc 8.3)
created:
12 years ago
visibility:
public

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