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

[Török Edwin]

On Fri, 23 Jul 2010 23:14:05 +0300
Török Edwin <edwintorok at gmail.com> wrote:

> 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.

And once libx.so is in the cache, I can update /usr/local/lib any
number of times, running just ldconfig -n to create the links.

> 
> > 
> > > 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

Sorry, second time should read:
time sudo ldconfig

real    0m0.142s
user    0m0.040s
sys     0m0.032s