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Message-ID: <42F07A02.4040308@familiehaase.de>
Date: Wed, 03 Aug 2005 10:02:10 +0200
From: "Gerrit P. Haase" <gerrit AT familiehaase DOT de>
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To: Warren Young <warren AT etr-usa DOT com>
CC: Cygwin-L <cygwin AT cygwin DOT com>
Subject: Re: Trouble making .so (undefined symbols)
References: <42F02793 DOT 8080109 AT etr-usa DOT com>
In-Reply-To: <42F02793.8080109@etr-usa.com>
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Warren Young wrote:

> I maintain MySQL++ (http://tangentsoft.net/mysql++/), a C++ API for 
> MySQL.  It builds fine under Cygwin when we create a static library, but 
> linking fails due to undefined symbols when we ask for a shared object.
> 
> The symptom is the libtool error "libtool: link: warning: undefined 
> symbols not allowed in i686-pc-cygwin shared libraries" when creating 
> the shared object itself.  I found some messages in the archive saying 
> that this can be fixed by using the link flag -no-undefined, but that 
> didn't help.
> 
> Now, libtool just warns here, doesn't return an error code.  No .so file 
> is created in the .libs directory.  Also, a mere 8-byte .a file is 
> created.  (It contains "!<arch>\n")
> 
> After this point in the MySQL++ build process, several example programs 
> are built.  When linking the first one, we get a spate of errors.  I 
> think this is secondary damage, because it tries to link to that .a 
> file, but it's basically empty.  Naturally g++ can't find any of the 
> symbol definitions it needs to link the program.
> 
> If you need to play with this to understand what I mean, download the 
> v2.0 beta 2 source from the URL above...it's LGPL.
> 
> How do I convince libtool to create the bloody .so file?

Use the Cygwin autotools (libtool-1.5.18, automake-1.9, autoconf-2.5x)
*and* add the flag -no-undefined to libmysqlpp_la_LDFLAGS?  And you
also need to use a shared libmysqlclient library.

Older versions of libtool as included with the tarball don't work.

Comments on the tarball:

  /usr/bin/install -c -m 644 'coldata.h' '/usr/include/coldata.h'
  /usr/bin/install -c -m 644 'compare.h' '/usr/include/compare.h'
  /usr/bin/install -c -m 644 'connection.h' '/usr/include/connection.h'
[...]
  /usr/bin/install -c -m 644 'vallist.h' '/usr/include/vallist.h'

You should put the headers into a separate directory, e.g.
/usr/include/mysql++.


Besides that all is fine:
$ ls -lRCGF ../.inst
../.inst:
usr/

../.inst/usr:
bin/  include/  lib/

../.inst/usr/bin:
cygmysqlpp-2.dll*

../.inst/usr/include:
coldata.h        defs.h         mysql++.h       row.h
compare.h        exceptions.h   noexceptions.h  sql_string.h
connection.h     field_names.h  null.h          stream2string.h
const_string.h   field_types.h  platform.h      string_util.h
convert.h        fields.h       qparms.h        tiny_int.h
custom-macros.h  lockable.h     query.h         type_info.h
custom.h         manip.h        resiter.h       vallist.h
datetime.h       myset.h        result.h

../.inst/usr/lib:
libmysqlpp.dll.a*  libmysqlpp.la*


The permissions of the .a and .dll.a files are wrong, I wonder if
libtool will ever get this right ;)

Send you a patchfile with PM.


Gerrit
-- 
=^..^=

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