Effects of RedHat up2date (generic)

I have a RH box and run up2date via cron. Recently it told me:

    glibc-2.2.4-31.i386.rpm:     Retrieved.
    glibc-common-2.2.4-31.i386.  Retrieved.
    Preparing...                 
    Installing /var/spool/up2date/glibc-common-2.2.4-31.i386.rpm...

    Installing /var/spool/up2date/glibc-2.2.4-31.i386.rpm...

The question is: after updating libraries, do I have to reboot to reload
them? It seems to me, if I have some binary in memory that uses some
library, which is also in memory, that I would have to restart every
binary running, or simply reboot, for the newer version on disk to take
effect.

George