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  1. int main() {
  2. 	{
  3. 		int arrayOfInt[3] = {0, 1, 2};
  4. 		int * toPtr{nullptr};
  5. 		int ** toPtrPtr{nullptr};
  6. 		const int ** toPtrPtrConst{nullptr};
  7.  
  8.  
  9. 		toPtr = arrayOfInt;
  10.  
  11. 		//toPtrPtr = &arrayOfInt; //KO, I assume because of 1.
  12. 		//toPtrPtr = static_cast<int**>(&arrayOfInt); //KO, same as above
  13. 	    toPtrPtr = reinterpret_cast<int**>(&arrayOfInt);
  14. 	    toPtrPtr = (int**)&arrayOfInt;
  15.  
  16. 	    //toPtrPtrConst = &arrayOfInt; //KO, still 1.
  17. 	    //toPtrPtrConst = static_cast<const int**>(&arrayOfInt); //KO, still 1.
  18. 	    toPtrPtrConst = reinterpret_cast<const int**>(&arrayOfInt); // (P1)
  19. 	        // it is supposed to be allowed to cast int** to const int* const*, not const int**
  20. 	        // Why is it working without requiring a const_cast to cast away the const qualifier?
  21. 	    toPtrPtrConst = (const int**)&arrayOfInt;
  22.  
  23. 	    //toPtrPtrConst = toPtrPtr; //KO, because of 2.
  24. 	    //toPtrPtrConst = reinterpret_cast<const int**>(toPtrPtr); //KO because of 2.
  25. 	        // so why is P1 allowed?
  26. 	}
  27.  
  28. 	{
  29. 	    const int arrayOfConstInt[3] = {0, 1, 2};
  30. 	    const int * toPtrConst{nullptr};
  31. 	    const int ** toPtrPtrConst{nullptr};
  32. 	    int * const * toPtrConstPtr{nullptr};
  33.  
  34. 	    toPtrConst = arrayOfConstInt;
  35.  
  36. 	    //toPtrPtrConst = &arrayOfConstInt; //KO, I assume because of 1.
  37. 	    //toPtrPtrConst = static_cast<const int**>(&arrayOfConstInt); //KO, same as above
  38. 	    //toPtrPtrConst = reinterpret_cast<const int**>(&arrayOfConstInt); // (P2) 
  39. 	        // Compiler error "casts away qualifiers", but which qualifier(s) would that cast away?
  40. 	    toPtrPtrConst = (const int**)&arrayOfConstInt;
  41.  
  42. 	    //toPtrConstPtr = &arrayOfConstInt; //KO, I assume because of 1.
  43. 	    //toPtrConstPtr = static_cast<int * const *>(&arrayOfConstInt); //KO, same as above
  44. 	    toPtrConstPtr = reinterpret_cast<int * const *>(&arrayOfConstInt); // (P3) 
  45. 	        // This one actually drops the const qualifier on the integer, but nevertheless it compiles
  46. 	    toPtrConstPtr = (int * const *)&arrayOfConstInt;
  47.  
  48. 	    //toPtrConstPtr = reinterpret_cast<int * const *>(&toPtrConst); // KO, because it casts away cost qualifier
  49. 	        // so why is P3 allowed?
  50. 	}
  51. }
Success #stdin #stdout 0s 16064KB
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https://ideone.com/JzWmAJ
language:
C++14 (gcc 8.3)
created:
8 years ago
visibility:
public

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