Learn C The Hard Way

Re:Learn C The Hard Way by palish on Saturday July 02, 2011 @11:13PM (#2722977)

They are numbers (either 32-bit or 64-bit). Nothing more, nothing less. I don't understand why you wouldn't want to think of them that way.

For example...

  const char* current = "ohai thar";
  const char* end     = current + strlen( current );

  assert( end >= current );
  size_t bytecount = (end - current);

(size_t is an unsigned type, so if 'end' is less than 'current', it will overflow. If you want to allow for that, use ptrdiff_t.)

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Re:Learn C The Hard Way by sausagefeet on Monday July 04, 2011 @01:41AM (#2725515)

No, they aren't numbers. The standard is quite clear on this. Consider old DOS architecture where you had a section and offset. Your code is also not well-defined C. C only lets you perform subtraction between two pointers in the same block, this code is at best implementation defined and worst undefined (I can't remember).

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