Re: Infos for Unix/Windows portable library making?

[Jason Curl]

On 25/04/2010 12:39, Ralf Wildenhues wrote:
> * Kārlis Repsons wrote on Sun, Apr 25, 2010 at 12:07:44PM CEST:
>    
> > On Sunday 25 April 2010 08:22:12 Ralf Wildenhues wrote:
> >      
> > > You can use libtool for portable creation of shared libraries.
> > > http://www.gnu.org/software/libtool is the place to go to,
> > > and address@hidden is the list to ask questions on.
> > >        
> > Thanks, I'll read that, just it's somewhat confusing how to start,
> > when there are three programs to deal with.
> >      
> Most trivial example, untested:
>
> cat>configure.ac<<\END
> AC_INIT([my-package], [1.0], [my-email-address])
> AC_CONFIG_AUX_DIR([build-aux])
> AC_CONFIG_MACRO_DIR([m4])
> AM_INIT_AUTOMAKE([foreign])
> LT_INIT([win32-dll])
>    
Does this affect the fact that I might also be targeting Unix like 
systems, as well as WinSDK?
> AC_PROG_CC
> AC_CONFIG_FILES([Makefile])
> AC_OUTPUT
> END
>
> cat>Makefile.am<<\END
> lib_LTLIBRARIES = libfoo.la
> libfoo_la_SOURCES = foo.c
> libfoo_la_LDFLAGS = -no-undefined
> bin_PROGRAMS = bar
> bar_SOURCES = bar.c
> bar_LDADD = libfoo.la
> END
>
> mkdir m4
> touch foo.c bar.c
>
> libtoolize -c
> autoreconf -vi
>
> ./configure --host=i586-mingw32msvc  # the prefix of my cross compiler
> make
> make install
>
>
>    
In addition, I'd add to my configure.ac scripts (libtool 2.2.6)

LT_LANG([Windows Resource])
AM_CONDITIONAL([HAVE_WINDRES], [test x$ac_cv_prog_ac_ct_RC != x])

And if you want your libraries to be usable by most other programming 
languages on Win32 (Win64 doesn't have this problem), I also add stdcall 
in configure.ac:

SHLIB_VERSION_ARG=""
if test x$ac_cv_c_compiler_gnu = xyes; then
   case "$host_os" in
      mingw* | cygwin*)
         SHLIB_VERSION_ARG="-Wl,--add-stdcall-alias"
         # You could also use "-Wl,--kill-at" and you'd only one 
export. But
         # we use --add-stdcall-alias to make linking easier.
                 ;;
          *)
                 ;;
   esac
fi
AC_SUBST(SHLIB_VERSION_ARG)

and in Makefile.am:

libfoo_la_LDFLAGS = -no-undefined @SHLIB_VERSION_ARG@

Then if you want to include resources in your DLL (to show a version 
number for example), put the following in Makefile.am

.rc.lo:
        $(LIBTOOL) $(AM_LIBTOOLFLAGS) $(LIBTOOLFLAGS) --tag=RC 
--mode=compile $(RC) $(RCFLAGS) $< -o $@

I actually create a rsrc.rc.in file that gets converted to an rsrc.rc 
file by configure that contains a bunch of internal information (e.g. 
debug, etc.) so I can audit my dlls better later.

You might also need to check for __MSVCRT__ to test if you're compiling 
for Windows or Posix (e.g. checking for Windows.h is unreliable as your 
users might use a native Cygwin compiler).

Cheers,
Jason.