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  1. #include <vector>
  2. #include <iostream>
  3.  
  4. using namespace std;
  5.  
  6. template <typename T>
  7. void log_alignment(const T* t)
  8. {
  9.   unsigned long long address = reinterpret_cast<unsigned long long>(t);  
  10.  
  11.   int max_alignment_check = 1024;
  12.   for (; max_alignment_check>1; max_alignment_check/=2)
  13.   {
  14.     if (address % max_alignment_check == 0)
  15.       break;
  16.   }
  17.  
  18.   std::cout << "Address 0x" << std::hex << address << " is " << std::dec << max_alignment_check << " bytes aligned.\n";
  19. }
  20.  
  21. struct B {
  22.   alignas(128) float data[32];
  23. };
  24.  
  25. int main()
  26. {
  27.   B b1;
  28.   B* b_ptr = new B;
  29.   B* b_arr = new B[2];  
  30.   std::vector<B> b_vec1(10);
  31.   std::vector<B> b_vec2(10);
  32.   B b2;
  33.  
  34.   log_alignment(&b1);
  35.   log_alignment(&b2);
  36.   log_alignment(b_ptr);
  37.   log_alignment(b_arr);  
  38.   log_alignment(b_vec1.data());
  39.   log_alignment(b_vec2.data());
  40. }
Success #stdin #stdout 0s 3472KB
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stdin
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Standard input is empty
stdout
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Address 0xffffffffbfbf2780 is 128 bytes aligned.
Address 0xffffffffbfbf2800 is 1024 bytes aligned.
Address 0xa047008 is 8 bytes aligned.
Address 0xa047090 is 16 bytes aligned.
Address 0xa047198 is 8 bytes aligned.
Address 0xa0476a0 is 32 bytes aligned.
https://ideone.com/XpgXyG
language:
C++14 (gcc 8.3)
created:
10 years ago
visibility:
public

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