Re: Library locations

[Russell Shaw]

Ralf Wildenhues wrote:
> Hello Braden, Russell,
>
> * Braden McDaniel wrote on Sun, Aug 05, 2007 at 08:27:07PM CEST:
> > On Mon, 2007-08-06 at 03:49 +1000, Russell Shaw wrote:
> > > I want it to be like:
> > >
> > >    System_LTLIBRARIES = modules/System/system.la
> > >    modules_System_system_la_SOURCES = modules/System/system.c
> > >    modules_System_system_la_LDFLAGS = -module
> > >
> > > That makes "modules/System/system.la" ok, but it still puts
> > > system.o and system.lo in the top level src directory.
>
> The latter feature is governed by the Automake option subdir-objects.
> Note that the option has existed for a long time, but its functionality
> has been improved lately, e.g., for non-C sources.  See the NEWS file
> for details.

Hi,
I forgot about that option.

> > Look again. That's entirely inconsistent with my experience with
> > automake's (1.10) behavior. The object file generated from the above
> > should be "modules/System/modules_System_system_la-system.lo".
>
> Then you have subdir-objects set.
>
> > > That means the program won't work in the uninstalled state,
> > > because dlopen is looking for system.o as modules/System/system.o.
> > That seems unlikely. dlopen should be looking for system.so. I don't
> > imagine it cares about the location of system.o.
>
> I agree with Braden here, dlopen should not care about object positions
> and things should work with subdir-objects and without.  If you have a
> failure setup, please show us how to reproduce it.

I have:

  AUTOMAKE_OPTIONS = subdir-objects

  System_LTLIBRARIES = modules/System/system.la
  modules_System_system_la_SOURCES = modules/System/system.c
  modules_System_system_la_LDFLAGS = -module
  AM_LDFLAGS = -export-dynamic

and now it works better with:

  modules/System/system.la
  modules/System/system.lo
  modules/System/system.o

generated.


However, the shared object that dlopen requires is in a new .libs directory:

  modules/System/.libs/system.o
  modules/System/.libs/system.so
  modules/System/.libs/system.so.0
  modules/System/.libs/system.so.0.0.0


Dlopen fails because it is looking for modules/System/system.so
When installed, i'll have the install location at:

  /usr/lib/$(pkglibdir)/System/system.so


Should i just have dlopen look for modules/System/.libs/system.so
and modules/System/system.so and use the first one that succeeds, or
is there a cleaner way for avoiding this?

Also, what's the best way to determine from within the program whether
it is currently installed or not?