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  1. namespace NAlignOf
  2. {
  3.     template <class TType>
  4.     struct TSizeIncrement: TType
  5.     {
  6.         char Increment;
  7.     };
  8.  
  9.     template <class TType, unsigned Start, bool Stop>
  10.     struct TIncreaseSizeImpl: TIncreaseSizeImpl<TSizeIncrement<TType>, Start,
  11.         sizeof(TSizeIncrement<TType>) != Start>
  12.     {
  13.     };
  14.  
  15.     template <class TType, unsigned Start>
  16.     struct TIncreaseSizeImpl<TType, Start, true>
  17.     {
  18.         typedef TType TType_;
  19.     };
  20.  
  21.     template <class TType>
  22.     struct TIncreaseSize: TIncreaseSizeImpl<TType, sizeof(TType), false>
  23.     {
  24.     };
  25.  
  26.     template <class TType>
  27.     struct TAlignOf
  28.     {
  29.         typedef typename TIncreaseSize<TType>::TType_ TIncreased_;
  30.         static const unsigned Value_ =
  31.             sizeof(typename TIncreaseSize<TIncreased_>::TType_)
  32.             - sizeof(TIncreased_);
  33.     };
  34. }
  35.  
  36. #include <iostream>
  37.  
  38. struct S0
  39. {
  40.     char c;
  41. };
  42.  
  43. struct S1
  44. {
  45.     char c;
  46.     short s;
  47. };
  48.  
  49. struct S2
  50. {
  51.     char c;
  52.     int i;
  53.     char c2;
  54. };
  55.  
  56. struct S3
  57. {
  58.     char c;
  59.     char c2;
  60.     int i;
  61. };
  62.  
  63. struct S4
  64. {
  65.     double d;
  66. };
  67.  
  68. struct S5
  69. {
  70.     char c;
  71.     long double d;
  72. }__attribute__((packed));
  73.  
  74. int main()
  75. {
  76.     std::cout << NAlignOf::TAlignOf<S0>::Value_ << std::endl;
  77.     std::cout << NAlignOf::TAlignOf<S1>::Value_ << std::endl;
  78.     std::cout << NAlignOf::TAlignOf<S2>::Value_ << std::endl;
  79.     std::cout << NAlignOf::TAlignOf<S3>::Value_ << std::endl;
  80.     std::cout << NAlignOf::TAlignOf<S4>::Value_ << std::endl;
  81.     std::cout << NAlignOf::TAlignOf<S5>::Value_ << std::endl;
  82. }
  83.  
  84.  
Success #stdin #stdout 0.01s 2724KB
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https://ideone.com/84ZGs
language:
C++ (gcc 8.3)
created:
12 years ago
visibility:
public

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