GCC bug with strftime

GCC bug with strftime

[Richard Troy]

Hi All,

It's been about eight months since I last posted to this list - hope
everyone is doing well...

I recently discovered a bug in strftime(). I downloaded a very recent copy
of cygwin and tried again, but it's still there. So, I'd like to report
it. I sent mail to the gcc-bugs list but nobody there seems to care, so I
thought I'd mention it here.

The problem is that this call fails to return an hour:

	strftime(IT,key,"%m/%d/%y %l:%M %p", brokentime);

The l% is supposed to represent a _space_ padded hour, as documented here:
http://www.gnu.org/manual/glibc-2.0.6/html_chapter/libc_17.html#SEC302

I wrote a test program to illustrate the problem - call it a "bug script:"

$ ./strftime

This program illustrates a bug with strftime as it fails to return the hour.
We are trying to use these flags: '%m/%d/%y %l:%M %p'
strftime returned: 01/09/03 :26 PM
The proper result: 01/09/03 3:26 PM
$

My workaround (in the bug script) gets the hour as two digits and then
tosses a leading zero... What a pain. -shrug-

I don't know how to check what version of the library I have, but I have
the following gcc compilers installed (as reported by cygcheck -s):

gcc                 3.2-3
gcc-mingw           20020817-4
gcc2                2.95.3-10

Please direct me on how I can get this information to someone who knows
what to do with it!

Thanks much,
Richard

-- 
Richard Troy, Chief Scientist
Science Tools Corporation
rtroy@ScienceTools.com, 510-567-9957, http://ScienceTools.com/



--
Unsubscribe info:      http://cygwin.com/ml/#unsubscribe-simple
Bug reporting:         http://cygwin.com/bugs.html
Documentation:         http://cygwin.com/docs.html
FAQ:                   http://cygwin.com/faq/

Re: GCC bug with strftime

[Christopher Faylor]

On Mon, Jan 13, 2003 at 05:46:20PM -0800, Richard Troy wrote:
>I recently discovered a bug in strftime(). I downloaded a very recent copy
>of cygwin and tried again, but it's still there. So, I'd like to report
>it. I sent mail to the gcc-bugs list but nobody there seems to care,

Why *would* anyone in gcc care about a library problem?  I believe that
they actually mentioned that the below was a GNU extension.  But,
regardless, the problem has nothing to do with gcc.

>The problem is that this call fails to return an hour:
>
>	strftime(IT,key,"%m/%d/%y %l:%M %p", brokentime);
>
>The l% is supposed to represent a _space_ padded hour, as documented here:
>http://www.gnu.org/manual/glibc-2.0.6/html_chapter/libc_17.html#SEC302

cygwin != glibc.  However, since cygwin uses newlib, and the people in
the newlib project are a cooperative bunch, maybe if you submitted a
patch, they'd consider adding it.  The mailing list is newlib at sources
dot redhat dot com.

cgf

--
Unsubscribe info:      http://cygwin.com/ml/#unsubscribe-simple
Bug reporting:         http://cygwin.com/bugs.html
Documentation:         http://cygwin.com/docs.html
FAQ:                   http://cygwin.com/faq/

Re: GCC bug with strftime

[Richard Troy]

> >I recently discovered a bug in strftime(). I downloaded a very recent copy
> >of cygwin and tried again, but it's still there. So, I'd like to report
> >it. I sent mail to the gcc-bugs list but nobody there seems to care,
>
> Why *would* anyone in gcc care about a library problem?  I believe that
> they actually mentioned that the below was a GNU extension.  But,
> regardless, the problem has nothing to do with gcc.

Doah! Yeah, glibc - what _was_ I thinking?! -smile-

> >The problem is that this call fails to return an hour:
> >
> >	strftime(IT,key,"%m/%d/%y %l:%M %p", brokentime);
> >
> >The l% is supposed to represent a _space_ padded hour, as documented here:
> >http://www.gnu.org/manual/glibc-2.0.6/html_chapter/libc_17.html#SEC302
>
> cygwin != glibc.  However, since cygwin uses newlib, and the people in
> the newlib project are a cooperative bunch, maybe if you submitted a
> patch, they'd consider adding it.  The mailing list is newlib at sources
> dot redhat dot com.

Thanks Christopher...

Richard

>
> cgf
>
> --
> Unsubscribe info:      http://cygwin.com/ml/#unsubscribe-simple
> Bug reporting:         http://cygwin.com/bugs.html
> Documentation:         http://cygwin.com/docs.html
> FAQ:                   http://cygwin.com/faq/
>


--
Unsubscribe info:      http://cygwin.com/ml/#unsubscribe-simple
Bug reporting:         http://cygwin.com/bugs.html
Documentation:         http://cygwin.com/docs.html
FAQ:                   http://cygwin.com/faq/

Re: GCC bug with strftime

[Richard Troy]

> > of cygwin and tried again, but it's still there. So, I'd like to report
> > it. I sent mail to the gcc-bugs list but nobody there seems to care, so I
> > thought I'd mention it here.
> >
> > The problem is that this call fails to return an hour:
> >
> > strftime(IT,key,"%m/%d/%y %l:%M %p", brokentime);
>
> hmmm...
>
> Are you sure that you are not passing a 'el' instead of a capital 'eye'
>
> it is real hard to differentiate in some typefaces
>
> note: python just calls the underlying 'C' strftime() implementation
>
> HTH
>
> Norman

Thanks for the thought, Norman.

The answer is yes, I have checked. The code works in my various RedHat
environments and has been for a long time. Also capital I is not what I
need; As your example illustrated, it returns a zero padded two digit
hour, but what I want/need is a non-padded hour, two or one digit,
depending. The reason I really care is because there are two programs that
have to talk to one another, one written in C and the other in Java. It
nearly doesn't matter which is which is which, they just have to agree on
the format. All was fine until I compiled the code on my cygwin
installation.

-shrug-

Richard


--
Unsubscribe info:      http://cygwin.com/ml/#unsubscribe-simple
Bug reporting:         http://cygwin.com/bugs.html
Documentation:         http://cygwin.com/docs.html
FAQ:                   http://cygwin.com/faq/

Re: GCC bug with strftime

[Norman Vine]

Richard Troy writes:
> 
> I recently discovered a bug in strftime(). I downloaded a very recent copy
> of cygwin and tried again, but it's still there. So, I'd like to report
> it. I sent mail to the gcc-bugs list but nobody there seems to care, so I
> thought I'd mention it here.
> 
> The problem is that this call fails to return an hour:
> 
> strftime(IT,key,"%m/%d/%y %l:%M %p", brokentime);

hmmm...

Are you sure that you are not passing a 'el' instead of a capital 'eye'

it is real hard to differentiate in some typefaces

note: python just calls the underlying 'C' strftime() implementation

HTH

Norman

$ python
Python 2.2.2 (#1, Dec 31 2002, 12:24:34)
[GCC 3.2 20020927 (prerelease)] on cygwin
Type "help", "copyright", "credits" or "license" for more information.
>>> import time
>>> time.strftime("%m/%d/%y %l:%M %p")
'01/13/03 :25 PM'
>>> time.strftime("%m/%d/%y %I:%M %p")
'01/13/03 09:26 PM'



--
Unsubscribe info:      http://cygwin.com/ml/#unsubscribe-simple
Bug reporting:         http://cygwin.com/bugs.html
Documentation:         http://cygwin.com/docs.html
FAQ:                   http://cygwin.com/faq/

Re: GCC bug with strftime

[Corinna Vinschen]

On Mon, Jan 13, 2003 at 07:00:07PM -0800, Richard Troy wrote:
> > > The problem is that this call fails to return an hour:
> > >
> > > strftime(IT,key,"%m/%d/%y %l:%M %p", brokentime);

I'm sorry to say that but...

> The answer is yes, I have checked. The code works in my various RedHat
> environments and has been for a long time. Also capital I is not what I

...just because it works under RH Linux it doesn't mean it's correct code.
The %l specifier character is not covered by SUSv3:

http://www.opengroup.org/onlinepubs/007904975/functions/strftime.html

which means, your usage of %l is non-portable.

Corinna

-- 
Corinna Vinschen                  Please, send mails regarding Cygwin to
Cygwin Developer                                mailto:cygwin@cygwin.com
Red Hat, Inc.

--
Unsubscribe info:      http://cygwin.com/ml/#unsubscribe-simple
Bug reporting:         http://cygwin.com/bugs.html
Documentation:         http://cygwin.com/docs.html
FAQ:                   http://cygwin.com/faq/

Re: GCC bug with strftime

[Richard Troy]

Thanks, Corinna,

...Good thing I've already written a work-around! -smile-

Gee, you never know what you might learn by posting on the wrong list!
-wink-

RT

-- 
Richard Troy, Chief Scientist
Science Tools Corporation
rtroy@ScienceTools.com, 510-567-9957, http://ScienceTools.com/

On Tue, 14 Jan 2003, Corinna Vinschen wrote:

> Date: Tue, 14 Jan 2003 10:05:46 +0100
> From: Corinna Vinschen <corinna-cygwin@cygwin.com>
> Reply-To: cygwin@cygwin.com
> To: Cygwin <cygwin@cygwin.com>
> Subject: Re: GCC bug with strftime
>
> On Mon, Jan 13, 2003 at 07:00:07PM -0800, Richard Troy wrote:
> > > > The problem is that this call fails to return an hour:
> > > >
> > > > strftime(IT,key,"%m/%d/%y %l:%M %p", brokentime);
>
> I'm sorry to say that but...
>
> > The answer is yes, I have checked. The code works in my various RedHat
> > environments and has been for a long time. Also capital I is not what I
>
> ...just because it works under RH Linux it doesn't mean it's correct code.
> The %l specifier character is not covered by SUSv3:
>
> http://www.opengroup.org/onlinepubs/007904975/functions/strftime.html
>
> which means, your usage of %l is non-portable.
>
> Corinna
>
>


--
Unsubscribe info:      http://cygwin.com/ml/#unsubscribe-simple
Bug reporting:         http://cygwin.com/bugs.html
Documentation:         http://cygwin.com/docs.html
FAQ:                   http://cygwin.com/faq/