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Date: Fri, 6 Feb 2004 19:35:08 +0100
From: Petr Vandrovec <vandrove@vc.cvut.cz>
To: viro@parcelfarce.linux.theplanet.co.uk
Cc: John Cherry <cherry@osdl.org>, linux-kernel@vger.kernel.org
Subject: Re: IA32 (2.6.2 - 2004-02-05.22.30) - 3 New warnings (gcc 3.2.2)
Message-ID: <20040206183508.GA3268@vana.vc.cvut.cz>
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On Fri, Feb 06, 2004 at 06:22:08PM +0000, viro@parcelfarce.linux.theplanet.co.uk wrote:
> 
> Umm...  How about
> 
> static inline void BUG() __attribute__((noreturn));
> 
> static inline void BUG(void)
> {
> 	__asm__ ....
> }

Unfortunately gcc thinks that it knows better than you whether function
can return or not. I attempted to use noreturn attribute in couple of
my projects, but it is useless - unless you terminate your function
with for(;;) or with call to _exit(), it won't work.

vana:~# more m.c
static inline void BUG() __attribute__((noreturn));

static inline void BUG(void) {
        __asm__ ("1: jmp 1b");
}

void main(void) {
        BUG();
}

vana:~# gcc -W -Wall m.c
m.c:7: warning: return type of `main' is not `int'
m.c: In function `BUG':
m.c:3: warning: `noreturn' function does return
vana:~#

(gcc version 3.3.3 20040125 (prerelease) (Debian))

> > Better to just initialize the variable to a default value and avoid the 
> > warning for now.
> 
> Alternatively, we can just turn the damn thing into
> 	if (dev->mode == IMM_NIBBLE || dev->mode = IMM_PS2)
> 		ports = 3;
> 	else
> 		ports = 8;
> and be done with that...

Yes.
				Petr Vandrovec