[Zlib-devel] [PATCH] Makefile.in: removed call to ldconfig

[Török Edwin]

On Fri, 23 Jul 2010 16:02:49 -0400
Mike Frysinger <vapier at gentoo.org> wrote:

> On Friday, July 23, 2010 15:28:08 Török Edwin wrote:
> > FWIW libtool runs ldconfig when installing the libraries, but does
> > so wrongly. It only works if you've installed the libraries in that
> > place before.
> 
> eh ?  previous installation status doesnt matter if it's just using
> ldconfig to generate appropate symlinks for the SONAMEs and such.  i
> think that's the only usage in libtool not for cache management.

It matters for the cache.
Here is an example on a Debian unstable system:

With -n it still tells me it can't open it
$ sudo ldconfig -n /usr/local/lib
$ /usr/local/bin/y
/usr/local/bin/y: error while loading shared libraries: libx.so: cannot
open shared object file: No such file or directory

Without -n it works
$ sudo ldconfig
$ /usr/local/bin/y
$

I created the lib like this:
$ cat >y.c <<EOF
int main(){return foo();}
EOF
$ cat >x.c <<EOF
int foo() {}
EOF
$ gcc -fPIC -shared x.c -o libx.so
$ gcc y.c -Wl,-R,../lib libx.so -o y
$ sudo cp y /usr/local/bin
$ sudo cp libx.so /usr/local/lib

Problem is that when running with -n it doesn't update the cache, so
when the app looks for libx.so, it doesn't find it.
ldconfig -p doesn't find it either.

> 
> > IMHO safest is to just run ldconfig with no params, zlib is doing
> > just that, so it is fine.
> 
> the obnoxious thing is that on any sizable systems, ldconfig can chew
> through the disk

Yes, but only the first time:

time sudo ldconfig

real    0m7.730s
user    0m0.064s
sys     0m0.092s

time sudo ldconfig

real    0m7.730s
user    0m0.064s
sys     0m0.092s



Best regards,
--Edwin