is this valid

void *p = &X; /* some thing */
p += 12;

and if so what does p now point to? I have (third party) code that does this (and compiles cleanly) and my guess is that the void * was treated as a char *. My trusty K&R is silent(ish) on the topic

EDIT: My little test app runs fine on gcc 4.1.1 and treats void * as char *. But g++ barfs

I know how to do it properly. I need to know if I have to clean this code base to find all the places its done.

BTW gcc -pedantic throws up a warning

Summary:

The C spec is ambiguous. It says that in terms of representation and use as function parameters void* =char*. But it is silent regarding pointer arithmetic.

  • gcc (4) permits it and treats it as char *
  • g++ refuses it
  • gcc -pedantic warns about it
  • vs2010 both c and c++ refuses it
c void-pointers
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