Subject: Re: problem building program: undef ref _imp__gettext
From: "Mark Paulus" <[email-masked]>
To: "cygwin mailing list" <[email-masked]>
Cc: "[email-masked]" <[email-masked]>
Date: Mon, 27 Aug 2001 14:51:05 -0600

Ok, I am guilty as charged of the "minimilistic" information.  
I am trying to build the debian dpkg source package, in an
effort to start a debian-cygwin project.  dpkg does use
autoconf, and as such, I ran it in it's default state.  I will
try re-running it with the pointers you gave me, and then 
see about what it takes to get it to build OOB.

Thanks for you time, and patience in this case with a 
very abrupt and hasty plea for help.

On Mon, 27 Aug 2001 14:14:26 -0400, Charles Wilson wrote:

>Mark Paulus wrote:
>
>> Thanks, that worked.  But, it makes me confused.
>> When I build this particular app under linux/debian,
>> it does NOT have the -lintl linker flag.  And when I add
>> it, the link fails.  But under cygwin, I need it.  
>> 
>> Can anyone out there help me reconcile the issues here.
>> (So I can go back to the source and either provide a patch,
>> or do whatever to get it to work in both environs).
>> 
>> Thanks.
>
>
>Take a close look at the output from the configure script.  Many 
>packages include a copy of the source for gettext (libintl) within their 
>own source distribution.  If configure can't find a system library for 
>it, it'll use the included source (some packages ALWAYS use the included 
>source unless explicitly instructed to use the system version).
>
>However, most autotool based packages treat the included gettext as a 
>"convenience library" which means that IF using the included gettext, it 
>doesn't link it via "-lintl" -- instead, it links in using a direct 
>reference to the static lib: "myobj.o otherobj.o 
>../gettext/intl/.libs/libintl.a moreobjs.o".
>
>If you add ANOTHER gettext library to the same link command (e.g. 
>../gettext/intl/.libs/libintl.a -lintl) you'll get duplicate symbol 
>definition and the link will fail.
>
>That's in an ideal world (linux).  On cygwin, the -lintl will find the 
>dll import library (with lots of __imp__foo symbols) but the 
>../gettext/intl/.libs/libintl.a is a static library and only has _foo 
>symbols.  Therefore, on cygwin, you CAN include both without error -- 
>because there IS no symbol duplication.  (Of course, since your object 
>files are only looking for the __imp__foo symbols, the 
>../get..../libintl.a is not used, even though it's specified.)  Welcome 
>to Windows.
>
>On cygwin, there are two possibilities:
>
>  1) configure DOES find the system gettext library so it does NOT build 
>the included version.  However (and here's the broken part) it neglects 
>to add -lintl to the generated link line.
>
>or
>
>  2) configure decides to go ahead an build the included gettext.  And 
>links against it using the ../gettext/intl/.libs/libintl.a method.  BUT: 
>for whatever reason, the *compilation* stage of the OTHER object files 
>are using the SYSTEM header files (/usr/include/gettext.h & friends) and 
>NOT the included header files (../gettext/include/*).
>
>These are different.  The SYSTEM header files assume you're going to 
>link against a DLL (thus, __imp__foo).  The locally included header 
>files don't know anything about DLL's -- so they only declare the _foo 
>symbols. not __imp__foo). Plus, the gettext library built from the 
>included sources is a static lib, so it doesn't have __imp__foo symbols, 
>only _foo symbols.
>
>the problem here is twofold:
>   a) system gettext headers different from "standard" gettext headers. 
>  This is unavoidable (for now) because of the whole DLL problem.
>   b) the package is using the system gettext headers when compiling its 
>local objects, EVEN WHEN using the local version of gettext.
>
>Solution:
>   a) workaround: Use "CFLAGS=-DGETTEXT_STATIC ./configure"  (this turns 
>the system gettext headers back into the "normal" gettext version).
>
>   b) convince your package that it ought to use its own headers when 
>using its own internal libraries, and not allow system overrides.  I'm 
>not sure exactly how to do this -- especially since EVERYTHING in this 
>message is guesswork, because you didn't provide a whole lot of 
>information.  "Problem building 'program':"  "This particular app" etc. 
>  A bit light on details, wouldn't you say?  I'm not even sure your app 
>is autotooled, or if it really does include its own gettext source.  I'm 
>just going by the common problems with gettext that have cropped up in 
>the past.
>
>   c) fix windows/cygwin dll process so that header-file hacks are no 
>longer necessary; build and release a new gettext package.  (This is my 
>job; i'll get to it eventually once the binutils changes/problems are fixed)
>
>--Chuck

--
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/