Re: A little confused about this...

[Steven Pritchard <steve@osiris.silug.org>]

crumb@midwest.net said:
> 	Can someone please explain as simply as humanly possible 
> what is this libc5, glibc stuff.  It is apparently something very 
> important, but I'll be d****d if I know what it is.  Thanks.

The libc5 to glibc (AKA libc6) transition probably isn't quite as huge
a deal as it might seem.  As somebody else already mentioned, the C
library is pretty important to the operation of the system, so changes
to it shouldn't be taken lightly, but for the most part glibc (which
is the GNU libc, BTW) is mostly compatible with the old Linux libc.
In fact, there has been a lot of code shared between the two for some
time.

When I say "mostly compatible", I mean at the source level.  At the
binary level, programs linked against libc5 still need it available.
However, unlike during the ugly a.out/libc4->elf/libc5 transition, you
don't need a full collection of libc5-based libraries lying around.
*Most* programs that use, for example, X libraries will work just fine
with glibc-based X libraries even though they were originally linked
against libc5-based X libraries.  The dynamic loader (ld.so) has to do
a lot of magic to pull that off though, so it doesn't always work.

At the source level, the only really major changes are that glibc
implements BSD signal() semantics, rather than SysV-style like libc5.
Also, glibc was designed to be thread-safe, unlike libc5 where that
was something of an after-thought.  Last, but certainly not least
(actually the main reason people are in such a hurry to move to
glibc), is that glibc is 64-bit clean and works properly on big- and
little-endian machines.  (In fact, glibc has been the only libc on
Linux/Alpha for quite some time.)

Anyway, if you have a libc5-based machine, the easiest way to make the
transition is all-at-once.  If possible, get a new version of your
distribution that's glibc-based and do an upgrade.  If you are running
a distribution without real package management
(*cough*Slackware*cough*), you may as well switch to a real
distribution now, since you'll be going through some pain anyway.

Hopefully all that helps.  :-)

Steve
-- 
steve@silug.org           | Linux Users of Central Illinois
(217)698-1694             | Meetings the 4th Tuesday of every month
Steven Pritchard          | http://www.luci.org/ for more info

--
To unsubscribe, send email to majordomo@silug.org with
"unsubscribe silug-discuss" in the body.