/lib/foo.so.X -> /usr/lib/foo.so

[Mark Kettenis]

   Date: Thu, 4 Sep 2003 14:10:50 -0700
   From: "David O'Brien" <obrien at FreeBSD.org>

   On Thu, Sep 04, 2003 at 11:27:15PM +0300, Ruslan Ermilov wrote:
   > On Thu, Sep 04, 2003 at 09:58:39PM +0300, Ruslan Ermilov wrote:
   > [...]
   > > The patch is not a problem (attached).  I've been looking at
   > > how our friends do this.  NetBSD has symlinks in /usr/lib to
   > > /lib, both to .so and .so.X, and their cc(1) and ld(1) don't
   > > look things in /lib.  Linux looks things up in both /lib and
   > > /usr/lib, and does not have symlinks from /usr/lib to /lib.
   > > 
   > There is a sad typo above: Linux *does* have symlinks from
   > /usr/lib to /lib, so both use /usr/lib for linking.

   What version of Linux are you using?  SuSE Enterprise Linux 8, and Red
   Hat Enterprise Linux 3 both do not have symlinks for libs from /usr/lib
   to /lib.  They use a different machanism:


       suse# cat /usr/lib/libc.so
	   /* GNU ld script
	      Use the shared library, but some functions are only in
	      the static library, so try that secondarily.  */
	   GROUP ( /lib/libc.so.6 /usr/lib/libc_nonshared.a )

Speaking as a (former) glibc developer (a true convert nowadays):

Well, libc is a special case since there are a few functions that
aren't provided by the shared libc, but are always linked statically.
Linux does this to be compatible with the System V ABI.

The whole thing is actually pointless since most interfaces in libc.so
aren't compatible with the System V ABI, so it's nothing but a
historical fart nowadays.

Anyway, I think you'll see a symlink for /usr/lib/libm.so.  At least
my SuSE Linux 8.2 does have it.

Mark