Pointer comparisons in C. Are they signed or unsigned?

by

Pointer comparisons cannot be signed or unsigned. Pointers are not integers.

C language (as well as C++) defines relative pointer comparisons only for pointers that point into the same aggregate (struct or array). The ordering is natural: the pointer that points to an element with smaller index in an array is smaller. The pointer that points to a struct member declared earlier is smaller. That’s it.

You can’t legally compare arbitrary pointers in C/C++. The result of such comparison is not defined. If you are interested in comparing the numerical values of the addresses stored in the pointers, it is your responsibility to manually convert the pointers to integer values first. In that case, you will have to decide whether to use a signed or unsigned integer type (intptr_t or uintptr_t). Depending on which type you choose, the comparison will be “signed” or “unsigned”.

More Related Contents:

  1. What is pointer to string in C?
  2. whats the difference between dynamic memory allocation and normal memory allocation?
  3. pointer to string concept in c [closed]
  4. Pointer manipulation inside function
  5. Changing address contained by pointer using function
  6. Why is the asterisk before the variable name, rather than after the type?
  7. What’s the difference between a VLA and dynamic memory allocation via malloc?
  8. Why does this implementation of offsetof() work?
  9. Why can’t I cast a function pointer to (void *)?
  10. Constant pointer vs Pointer to constant [duplicate]
  11. Function to dynamically allocate matrix
  12. Using fseek with a file pointer that points to stdin
  13. What happens in OS when we dereference a NULL pointer in C?
  14. Pointer vs array in C, non-trivial difference
  15. Passing arrays and matrices to functions as pointers and pointers to pointers in C
  16. Is it good practice to free a NULL pointer in C? [duplicate]
  17. Comparing two strings in C? [duplicate]
  18. change pointer passed by value
  19. Why can I change the value of a const char* variable?
  20. Accesing a 2D array using a single pointer
  21. Triple pointers in C: is it a matter of style?
  22. C: pointer to array of pointers to structures (allocation/deallocation issues)
  23. How to explain C pointers (declaration vs. unary operators) to a beginner?
  24. Why does NSError need double indirection? (pointer to a pointer)
  25. What is the real difference between Pointers and References?
  26. Does C have an equivalent of std::less from C++?
  27. free a double pointer
  28. pointer default value .?
  29. Is it possible to store the address of a label in a variable and use goto to jump to it?
  30. C pointer notation compared to array notation: When passing to function

Leave a Comment