4 ms·

Just in case anyone is curious, the error was having `sizeof(key - r)` instead of `sizeof(key) - r` Rookie mistake!

• riffraff 14y ago
  I wonder, what sort of technology would have avoided this? The "key -r" bit seems a bit suspicious type wise
  • marshray 14y ago
    Yeah, why would you care about the size of a temporary arithmetic expression?
    • ElectroPrime 14y ago
      Well... sizeof of an expression is mostly useful for not repeating yourself in cases when you need the size of a type you already have some way of referencing, as in a = malloc(sizeof(*a)); It's also useful for various hacks (stuff like compile-time assert macros), since it doesn't evaluate the expression, only its type.
      • marshray 14y ago
        Sure, I can think of plenty of ways it could arise via metaprogramming. I don't know if I would want such a warning enabled in my own template-heavy C++ code. But it perhaps it could be useful for those following the NetBSD style. :-)
      • pizza_ 14y ago
        sizeof is an operator, no need for the inner parens.
  • Tobu 14y ago
    -Wsizeof-pointer-memaccess (Clang and GCC 4.8) is the only sizeof-related warning I know of, which warns about some cases where both pointer and size are immediately passed to a handful of builtin functions (in GCC, some among mem…, str…, s…printf). C's typing is much too weak for -Wsizeof-pointer-memaccess to be generally useful. Without getting into typing, a simple warning: arithmetic inside sizeof would catch this. I don't think it would catch much noise, I don't see any useful uses of pointer arithmetic immediately inside a sizeof. It's a bit specific though, are there more functions that would benefit as well?