Date: Tue, 28 Oct 2003 22:28:24 +1100 (EST) From: Bruce Evans <bde@zeta.org.au> To: Dag-Erling =?iso-8859-1?q?Sm=F8rgrav?= <des@des.no> Cc: Peter Wemm <peter@FreeBSD.org> Subject: Re: cvs commit: src/usr.bin/chat Makefile Message-ID: <20031028222117.X4879@gamplex.bde.org> In-Reply-To: <xzpbrs1afvz.fsf@dwp.des.no> References: <200310260449.h9Q4nwm9016893@repoman.freebsd.org> <20031026171515.P17272@gamplex.bde.org> <xzpu15w9rhk.fsf@dwp.des.no> <20031027152156.Y21211@gamplex.bde.org> <xzpbrs1afvz.fsf@dwp.des.no>
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On Tue, 28 Oct 2003, Dag-Erling [iso-8859-1] Smørgrav wrote:
> Bruce Evans <bde@zeta.org.au> writes:
> > On Sun, 26 Oct 2003, Dag-Erling [iso-8859-1] Smørgrav wrote:
> > > In the meantime, now that we have a working fabsl(3), we can add
> > > -fno-builtin to CFLAGS in bsd.sys.mk.
> > That would just break the warning and pessimize anything that is optimized
> > by the builtins.
>
> The warnings are wrong more often than not... particularly the *lack*
> of warning when you use a builtin function without including the
> header that declares it.
But that is fixed:
%%%
Script started on Tue Oct 28 22:20:44 2003
ttyp0:bde@besplex:/tmp> cat z.c
int
main(void)
{
return (strlen("123"));
}
ttyp0:bde@besplex:/tmp> cc -O -S -Wimplicit z.c
z.c: In function `main':
z.c:4: warning: implicit declaration of function `strlen'
ttyp0:bde@besplex:/tmp> cat z.s
.file "z.c"
.text
.p2align 2,,3
.globl main
.type main, @function
main:
pushl %ebp
movl %esp, %ebp
subl $8, %esp
andl $-16, %esp
movl $3, %eax
leave
ret
.size main, .-main
.ident "GCC: (GNU) 3.3.1 [FreeBSD]"
ttyp0:bde@besplex:/tmp> exit
Script done on Tue Oct 28 22:20:58 2003
%%%
Note that it uses the builtin to just return 3 after emitting the warning.
Similarly for `return (log(3));`. gcc doesn't do the log() inline, at
least on i386's with no options, but it knows to pass 3.0 and convert
the return value to int.
Bruce
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