Re: MinGW DLLs and autoconf parsing

[Jason Curl]

Thanks Roumen, I've taken the same route as you've mentioned although 
it's hackish.

I'm hoping someone from the libtool developer community can comment.

Roumen Petrov wrote:
> Jason Curl wrote:
> > Hello,
> >
> > Recently some info was posted about using resource files with Windows 
> > compilers. I'm trying to generate a reasonably simple Version 
> > resource and there's some information I'm not sure how I can extract 
> > from the build process. I'm using libtool-1.5.27a on MSYS-1.0.10 with 
> > MinGW-5.1.4.
> >
> >
> > Question 1:
> > One of the fields is "OriginalFilename". When the shared DLL is 
> > built, it is installed "libfoo-1.dll". I've created a "rsrc.rc.in" 
> > file that autoconf generates for me, substituting information from 
> > the build process directly into this resource file.
> >
> > However, how might I get the name of the library before it is built?
>
> You may create library with name "libfoo.dll" if you call make with
> LDFLAGS="--avoid-version".
> Also you may set this flag in configure script for mingw host.
> libtool don't preserve LIBRARY statement specified by def-file.
>
> The string "-1" is suffix appended by libtool for cygwin/mingw host. The
> number is equal to  "$current - $age" from version info.
Avoiding the version isn't a problem. I see that there's an advantage of 
using the version. But libtool generates a name, and is there an API to 
get this name? For different architectures, the naming scheme changes. 
Or do I need to install and parse the ".la" file to reliably get the 
name? Then I can't do this within 'configure.ac' where I do need the 
name (to generate a resource file from x.rsrc.in).

And right now, I've just had to read the libtool source and figure it 
out. I expect breakages the next time I upgrade..
> > Question 2:
> > The second task is the versioning. There are two fields, both of the 
> > format:
> > FILEVERSION major,minor,revision,build
> >
> > I need to substitute them based on the version information given to 
> > libtool during the linking phase.
> > WINSERLOG_VERSION_INFO="1:0:0"
> > AC_SUBST(WINSERLOG_VERSION_INFO)
> >
> > How can I convert the string "1:0:0" to a major.minor.revision field? 
> > How does this work?
>
> awk, sed , shell ?
> - born shell sample:
> IFS=:; set -- `echo a:b:c`; echo $1.$2.$3
Again, reading libtool it defines $major, $minor, $revision, but 
depending on the platform it changes. The string above is $current, 
$revision, $age, which is not the same thing. And I remember that it 
some versions of libtool for some particular platform it's really not 
obvious. Such a feature is not Windows specific. I have an API in most 
of my libraries to get the version information

Right now, I've just had to do:
$major = $current - $age  (c-a)
$minor = $age (a)
$rev = $revision (r)
> > Question 3:
> > As the libtool --tag=RC doesn't work for 1.5.27a (it complained about 
> > an unknown tag), I wrote the rule:
>
> I guess that configure script is without macro AC_LIBTOOL_RC
Tried that already. I think this is probably a new feature for 
Libtool-2.x I ended up using the tag CC. I don't really know if using 
tag CC is really intended, or if there could be a breakage later with a 
different compiler toolset (other than gcc, or with a cross compiler)
> > .rc.lo:
> >         $(LIBTOOL) $(AM_LIBTOOLFLAGS) $(LIBTOOLFLAGS) --tag=CC 
> > --mode=compile $(RC) $(RCFLAGS) $< -o $@
> >
> > where RC=windres and RCFLAGS is empty. It works, but is it safe? I 
> > don't know when MinGW will upgrade the autotools.
>
> May be you need two rules : one to create %.lo file and one for object
> file (%.o):
> -------------------
> RCFLAGS = $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(AM_CPPFLAGS) 
> $(CPPFLAGS)
> RCCOMPILE = $(RC) $(RCFLAGS)
> LTRCCOMPILE = $(LIBTOOL) --mode=compile --tag=RC $(RCCOMPILE)
>
> .rc.lo:
>     $(LTRCCOMPILE) -i "$<" -o "$@"
>
> .rc.o:
>     $(RCCOMPILE) -i "$<" -o "$@"
> -------------------
.o files don't make sense for static libraries in this case, so I'm 
happy to see that for the static case it isn't even used and everything 
seems to work.
> > Thanks & Best Regards,
> > Jason.
>
> Roumen
Thanks Roumen.