Re: [PATCH] Trivial warning fix for imap-send.c

[Horst von Brand <vonbrand@inf.utfsm.cl>]

Jeff King <peff@peff.net> wrote:

[...]

> A void pointer is guaranteed to be able to hold any type of pointer
> (either char * or struct foo * or whatever). The declaration of malloc
> indicates a return of void *. On a platform where it matters, the
> compiler generates code so that 
>   struct foo *bar = malloc(100);
> converts the void * pointer into the correct size (in the same way that
> assigning between differently sized integers works).

Right.

> This breaks down with variadic functions, which have no typing
> information. So doing this:
>   execl("foo", "bar", my_struct_foo);
> doesn't give the compiler a chance to do the implicit cast and you get
> subtle breakage (in the same way that you would if you passed a long to
> a variadic function expecting a short).

It just passes 3 "void *"'s, and casts back. What is so strange?
-- 
Dr. Horst H. von Brand                   User #22616 counter.li.org
Departamento de Informatica                     Fono: +56 32 654431
Universidad Tecnica Federico Santa Maria              +56 32 654239
Casilla 110-V, Valparaiso, Chile                Fax:  +56 32 797513