[sane-devel] updating sane on Ubuntu 12.04 64 bit leaves xsane using old sane software

[Richard Ryniker]

When dynamic load libraries are changed (e.g. with the new files you
installed in /usr/lib/x86_64-linux-gnu/) it is necessary to execute

  /sbin/ldconfig

to update the cache used by the loader.  When libraries are updated by
package managers (aptget, dpkg, yum and others), this is done
automatically; when you build something yourself, it usually is not, in
order to allow a person to test the application before it is shared by
all users.

Of course, an application can be tested where it is built, before "make
install" is run, and that is clearly wise, but it also is useful to test
after "make install" and before general use, in case something in the
installation process is not right.

  /etc/ldconfig -p

displays the current cache contents, but does not change the cache.
Therefore, use of this command before and after /etc/ldconfig will
divulge what may have changed in the cache.