Message-ID: <207491.83862.qm@web25504.mail.ukl.yahoo.com>
Date: Thu, 5 Nov 2009 11:07:21 +0000 (GMT)
From: Marco Atzeri <marco_atzeri AT yahoo DOT it>
Subject: Re: question on libtool usage/limitation
To: cygwin AT cygwin DOT com, Dave Korn <dave DOT korn DOT cygwin AT googlemail DOT com>
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--- Gio 5/11/09, Dave Korn  ha scritto:

>=20
> > The current link command is
> > /bin/sh ../libtool
> --tag=3DCXX=A0=A0=A0--mode=3Dlink g++-4 -g
> -O2=A0=A0=A0-DHAVE_CONFIG_H
> -mieee-fp=A0=A0=A0-Wall -W -Wshadow
> -Wold-style-cast -Wformat -g -O2=A0 -g -O2 -release
> 3.3.50+ -no-undefined -o liboctave.la -rpath
> /usr/local/lib/octave-3.3.50+=A0 [huge list of
> x.lo]=A0 ../libcruft/libcruft.la=A0 -lcholmod
> -lumfpack -lamd -lcamd -lcolamd -lccolamd -lcxsparse
> -larpack -lqrupdate=A0 -lfftw3 -lfftw3f -llapack -lblas
> -lreadline -lncurses=A0 -L/usr/lib -lpcre -ldl
> -L/bin/../lib/gcc/i686-pc-cygwin/4.3.4 -L/bin/../lib/gcc
> -L/usr/lib/gcc/i686-pc-cygwin/4.3.4
> -L/bin/../lib/gcc/i686-pc-cygwin/4.3.4/../../.. -lm
> -lgfortranbegin -lgfortran -lcygwin -luser32 -lkernel32
> -ladvapi32 -lshell32=A0 -lwsock32 -lm=A0 -lwsock32
> -lwsock32 -lm=A0 -lwsock32
> >=20
> > but the disappointing outcome is
> >
> -------------------------------------------------------
> > *** Warning: This system can not link to static lib
> archive
> /bin/../lib/gcc/i686-pc-cygwin/4.3.4/libgfortranbegin.la.
> > *** I have the capability to make that library
> automatically link in when
> > *** you link to this library.=A0 But I can only do
> this if you have a
> > *** shared version of the library, which you do not
> appear to have.
> > libtool: link: rm -fr=A0
> .libs/liboctave.la.lnkscript
> >=20
> > *** Warning: linker path does not have real file for
> library -lcholmod.
> > *** I have the capability to make that library
> automatically link in when
> > *** you link to this library.=A0 But I can only do
> this if you have a
> > *** shared version of the library, which you do not
> appear to have
> > *** because I did check the linker path looking for a
> file starting
> > *** with libcholmod and none of the candidates passed
> a file format test
> > *** using a file magic. Last file checked:
> /usr/lib/libcholmod.a
> >=20
> > [repeated for all the static libs]
> >
> -------------------------------------------------------
> >=20
> > Does libtool on cygwin require special setting to
> overcome such=20
> > problem ? On linux platform the build seems to be
> fine.
>=20
> =A0 On Linux probably it's all shared libs and it
> doesn't matter if symbols
> don't get resolved in the final link because they'll still
> be resolved at
> load-time; on Windows of course everything must be resolved
> in the final link,
> which limits libtool's options if it can't find the
> expected sorts of
> libraries to link against.
>=20
> > Moreover for Fortran libgfortranbegin.la=20
> > is currently a static lib so I not easily overcome
> > the issue changing it to a dll.
>=20
> =A0 Perhaps you'd better show us how you've defined the
> libtool primaries,
> liboctave_la_LINK/LIBS/LDADD/xFLAGS/whatever in
> particular.=A0 IIUC, depending
> which one you use (and whether it's a full path to the .a
> file or a -lXXX
> option), libtool interprets what you mean as either 1)
> please add the contents
> of this library to the link, or 2) make the output library
> dependent on this
> input library.=A0 You're getting 2) when you want 1),
> and it's certainly to be
> expected that attempting 2) with plain static archives that
> don't even have
> libtool .la control scripts wouldn't work right on PE.
>=20
> =A0 =A0 cheers,
> =A0 =A0 =A0 DaveK
>=20

Hi Dave,=20
Thank for the clarification, I was suspecting something=20
like that.

I tried to "convince" libtool to use the static libraries,
building and ad hoc .la script, but I didn't fooled it.

I suppose that I should replace the simple "-llibcholmod"
with one of the methods mentioned in the libtool documentation:


`-Wc,FLAG'
`-Xcompiler FLAG'
     Pass a linker-specific flag directly to the compiler.

`-Wl,FLAG'
`-Xlinker FLAG'
     Pass a linker-specific flag directly to the linker.

`-XCClinker FLAG'
     Pass a link-specific flag to the compiler driver (CC) during
     linking.

but I need to understand, which and how to specify the static lib
/usr/lib/libcholmod.a (and the others)

Regards
Marco


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