Re: Cygwin & libltdl

[Eric Blake]

Bob Friesenhahn <bfriesen <at> simple.dallas.tx.us> writes:

> 
> GraphicsMagick has been tracking CVS libtool pretty closely.  I have 
> not tried building under Windows in quite a while.  I notice that the 
> Cygwin build fails when building loadable modules and lists all of the 
> externals that the loadable module needs from the main library.  I 
> used nm on magick/.libs/libGraphicsMagick.dll.a (the main library the 
> module links against) and notice that all of the symbols listed there 
> are from libltdl.  For some reason, none of the normal symbols which 
> should be in the library are there.  Using nm on 
> magick/.libs/cygGraphicsMagick-2.dll shows the expected symbols so it 
> seems that the link library came up short.

Sounds like you are falling into the same predicament as CVS M4.

http://lists.gnu.org/archive/html/m4-patches/2007-02/msg00026.html

My guess is that the solution, at least until libtool is improved to not 
explicitly mark libltdl symbols for export when compiling libltdl as a 
convenience library, is to either also mark all your symbols for export, or to 
add this to your Makefile.am (which is what I did for M4):

# The -export-symbols-regex ".*" is a hack to work around the
# fact that on cygwin, the convenience library libltdl exports symbols,
# which effectively disables the auto-exporting of all other symbols.
# Revisit this if libtool on cygwin improves.
# See http://lists.gnu.org/archive/html/libtool-patches/2007-02/msg00062.html
AM_LDFLAGS     += -export-symbols-regex ".*"

-- 
Eric Blake