Re: [PATCH 2/2] remove NORETURN from function pointers

From: Johannes Sixt <j.sixt@viscovery.net>
Date: Sep 14, 2009, 13:09 UTC
Message-ID: <4AAE4087.5030607@viscovery.net>
In-Reply-To: <40aa078e0909140532q693a7f9qc3d9b1d354cac356@mail.gmail.com>

Erik Faye-Lund schrieb:

Show 11 quoted lines

> Compiling the following code gives a warning about unreachable code,
> so it's clear that msvc doesn't simply ignore the directive. I'm not
> saying that anyone suggested otherwise, I just wanted to know for
> sure.
> 
> #include <stdio.h>
> #include <stdlib.h>
> void (*exit_fun)(int) = exit;
> void __declspec(noreturn) die(void);
> void die(void) { exit_fun(1); }
> int main(void) { printf("hello!\n"); die(); printf("world!\n"); }

In order to countermand any clever optimizations you should make it

-void (*exit_fun)(int) = exit; +extern void (*exit_fun)(int);

(of course, this fails to link). But if this results in only *one* warning (that the printf() call is unreachable), then I wouldn't bother with this problem anymore, because you really should also have been warned that a __declspec(noreturn) function actually does return.

-- Hannes