Re: Checking libraries in multiple places -- frusturated by the cache

[Vaclav Haisman]

Hi,
is there any chance that such machinery will ever be a part of autoconf?

Vaclav Haisman

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On Sun, 25 Feb 2001, Lars Hecking wrote:

> Robert A. Knop Jr. writes:
> > I'm fairly new to autoconf, so this may be a clueless question.
> > 
> > What I'm trying to do is check a few standard places for a library
> > and then set a variable (*not* LIBS, but my own) based on where this
> > library was found.  To this end, I have the following code in
> > configure.in:
> > 
> >   for i in '' -L$prefix/lib -L$prefix/pgsql/lib; do
> >     found=''
> >     AC_MSG_RESULT("Looking for Postgres library in $i")
> >     AC_CHECK_LIB(pq, PQconnectdb, found=1, found='', $i)
> >     if test $found; then
> >       pgsql_lib=$i
> >       break
> >     fi
> >   done
> >   if test $found; then
> >     AC_MSG_RESULT("Postgres library found: $pgsql_lib")
> >   else
> >     AC_MSG_ERROR("Postgres library not found!")
> >   fi
> > 
> > The problem I'm having is that after the first test fails, the generated
> > configure script never really tests the other places I'm looking for the
> > library-- because the failure of the first test is cached, so it thinks it
> > doesn't need to do the test again!
> > 
> > Is there some way I can tell configure to throw out the previous cached
> > value of this test before tryiing the AC_CHECK_LIB test again?  I haven't
> > found anything in the documentation which would indicate how one does
> > this.
> > 
> > I don't want to include the result of the test in LIBS, I want to set a
> > different value; this is why I don't just use AC_SEARCH_LIBS.  (In any
> > event, AC_SEARCH_LIBS says it sets -lsomething, not -Lsomething.)
> 
>  I have been doing something very similar for gnuplot: two macros, one
>  for headers, one for libs, with a for loop around non-caching and silent
>  versions of the resp. autoconf macros. See attached. I think I wrote
>  this stuff before AC_SEARCH_LIBS became part of autoconf.
> 
>