Date: Wed, 18 Jan 1995 11:06:59 +0000 (GMT) From: Doug Rabson <dfr@render.com> To: "Paul F. Werkowski" <pw@snoopy.MV.COM> Cc: freebsd-hackers@freefall.cdrom.com Subject: Re: old vfprintf bug back again in 2.x Message-ID: <Pine.BSF.3.91.950118110149.3845C-100000@minnow.render.com> In-Reply-To: <199501151945.OAA07055@snoopy.mv.com>
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On Sun, 15 Jan 1995, Paul F. Werkowski wrote:
>
>
> A bug that was lurking in lib/libc/stdio/vfprintf.c prior to FreeBSD 1.1
> is now again hiding in the 2.0 and -current source. The bug is demonstrated
> by this code:
>
>
>
> int main()
> {
> int FPRC = 16;
> double d = 0;
> printf( "%*.*e\n",FPRC+7,FPRC,d);
> }
>
> which results in
> 0e+00
>
> instead of the correct
> 0.0000000000000000e+00
>
> This breaks the AKCL (now GCL) compile/load feature.
>
> I looked at the considerable differences between the 1.1 and 2.0 versions
> of vfprintf and think I have reproduced the previous fixes. At least the
> modified version passes the GCL test. Perhaps some official bug fixer can
> look at this and commit to current /usr/src/lib/libc/stdio/?
>
> Paul
>
> [patch deleted]
I looked into this and I believe that this patch does the same job:
*** /usr/src/lib/libc/stdio/vfprintf.c Fri May 27 05:57:31 1994
--- vfprintf.c Mon Dec 19 16:46:42 1994
***************
*** 507,512 ****
--- 507,514 ----
prec = (prec == -1) ?
DEFPREC + 1 : prec + 1;
/* FALLTHROUGH */
+ if (prec != 0)
+ flags |= ALT;
goto fp_begin;
case 'f': /* always print trailing zeroes */
if (prec != 0)
It certainly helps GCL anyway. Unless you have any objections, I will
commit this smaller patch as it seems to be a bit less intrusive.
--
Doug Rabson, RenderMorphics Ltd. Mail: dfr@render.com
Phone: +44 71 251 4411
FAX: +44 71 251 0939
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