Re: [PATCH] Do without union of variable length arrays.

[Alexander Cherepanov]

On 2015-09-17 12:40, Mark Wielaard wrote:
* Now const size_t is used instead of const int for malloc argument type.

Thanks. I am still interested in the overflow issue. I believe since we
are using unsigned arithmetic and we know the size is always > 0, it
should be as simple as doing:

   const size_t elem_size = ... sizeof (...);
   const size_t bytes = num * elem_size;
   if (unlikely (bytes / elem_size != num))
     return E_NOMEM;
   ... malloc (bytes);

Sorry, I'm late to the party but why hot check it before multiplication 
in a usual way:

if (num > SIZE_MAX / elem_size)
  return E_NOMEM;

IIUC elem_size is a compile time constant so the whole division is 
computed by compiler.

--
Alexander Cherepanov