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  1. #include <iostream>
  2.  
  3. struct Settings
  4. {
  5.     Settings(int v_) : v(v_) {}
  6.     int v;
  7. };
  8.  
  9. //http://stackoverflow.com/a/11255852
  10. #define useHardwareWith(settings)                   \
  11. acquireHardware(settings);                          \
  12. for(                                                \
  13.   struct                                            \
  14.   {                                                 \
  15.     struct inner									\
  16.     {												\
  17.       inner() : done_(false)						\
  18.       {												\
  19.       }												\
  20.       void run()									\
  21.       {												\
  22.       	done_ = true;								\
  23.       }												\
  24.       ~inner()										\
  25.       {												\
  26.       	releaseHardware();							\
  27.       }												\
  28.       bool done_;									\
  29.     };   											\
  30.     bool done() const                               \
  31.     {                                               \
  32.       return inner_.done_;                          \
  33.     }                                               \
  34.     bool run()                                      \
  35.     {                                               \
  36.       inner_.done_ = true;                          \
  37.     }                                               \
  38.     inner inner_;                                   \
  39.   } magic; !magic.done() ; magic.run())
  40.  
  41. void acquireHardware(const Settings& settings)
  42. {
  43.   std::cout << "acquire(" << settings.v << ")\n";
  44. }
  45.  
  46. void releaseHardware()
  47. {
  48.   std::cout << "release()\n";
  49. }
  50.  
  51. void doHardwareStuff(const Settings& settings)
  52. {
  53.   useHardwareWith(settings)
  54.   {
  55.   	if (settings.v == 0)
  56.   	{
  57.   		std::cout << "side-exit\n";
  58.   		return;
  59.   	}
  60.     std::cout << "Doing important hardware stuff\n";
  61.   }
  62. }
  63.  
  64. int main()
  65. {
  66.   Settings settings(0);
  67.   doHardwareStuff(settings);
  68.   doHardwareStuff(Settings(1));
  69. }
  70.  
Success #stdin #stdout 0s 3296KB
comments (?)
stdin
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Standard input is empty
stdout
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acquire(0)
side-exit
release()
acquire(1)
Doing important hardware stuff
release()
https://ideone.com/z3Qm8a
language:
C++ (gcc 8.3)
created:
10 years ago
visibility:
public

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