Re: checking for libraries that link but do not run

[Bob Friesenhahn]

On Mon, 5 Oct 2009, Ben Pfaff wrote:
> To try to head off the problem, I'm thinking about putting
> something like this after each command that adds to LIBS:
>    AC_RUN_IFELSE([AC_LANG_PROGRAM([], [])],
>                  [:],
>                  [AC_MSG_FAILURE([Cannot run program linked against $LIBS.])],
>                  [:])
>
> Am I on the right track?  It seems to me that there should
> already be a mechanism to help with this, but I do not see one.

This is a rather complex issue since the problem can be corrected by 
LD_LIBRARY_LFLAGS, ldconfig/crle, by formally installing the library, 
or by libtool at link time.  Since autoconf does not use libtool in 
its testing, it does not benefit from the extra smarts provided by 
libtool, and so autoconf tests are more fragile.  For example, 
autoconf can't know about library dependencies that libtool may be 
able to figure out later (via installed .la files) and so the 
configure script developer needs to provide way to add all of these 
dependencies to LIBS.

In summary, your idea seems nice, but it might block builds which 
would otherwise succeed and work.

Bob
--
Bob Friesenhahn
address@hidden, http://www.simplesystems.org/users/bfriesen/
GraphicsMagick Maintainer,    http://www.GraphicsMagick.org/