dynamic libraries, libtool

[OSX User]

Trying to perform a somewhat whimsical "touch-up" provided a warning
about my ignorance of OSX. It seemed like a good idea to update the
existing /lib/libz1.1.3-dylib to the level of libz.1.1.4 that came with
a perl module.

My first question is whether there is a little more documentation on
dynamic libraries than the "ld" and "libtool" man pages.

The first minor problem arose when I first tried to create the dynamic
library. Using "libtool -dynamic -o lib.dyn *.o", I was told I had a
bunch of undefined names. Since these names looked familiar, I just
threw a "-lc" on the "libtool" command, and the warnings went away.
Will this come back to haunt me? Will this work whether or not
"-dynamic" was used to compile the "*.o" files or the "-lc" files?

Then I archived the old "libz.1.1.3", and found out existing programs
don't magically recognize "libz.1.1.4". How can I get old programs to
use "1.1.4"? There are some symbolic links in "/usr/lib", but it seems
they aren't used. Or is it wrong to assume compatibility? Will I have
to keep "1.1.3" forever?

Are the "current/compatibility_version" flags in libtool purely
informational, requiring special programming by the library user in
order to be useful? Who looks at "install_name"?

Everything seems OK for the moment, but I wonder if something
#($*&saKHGsd *$&HEue SDxxW KF sjaUeefhjsdf#$%$(!)*
~*^^^^_
..
..
..

[Mike Hall]

OSX User wrote:

>Then I archived the old "libz.1.1.3", and found out existing programs
>don't magically recognize "libz.1.1.4". How can I get old programs to
>use "1.1.4"?

I use 'otool -L' on the binary to see what shared-libs it uses.
One can hope that the binary would like to find the 'libz' without a version number,
but ...

> There are some symbolic links in "/usr/lib", but it seems they aren't used.

Are you sure?

$ ls -l /usr/lib/*libz*
-rwxr-xr-x 1 root wheel 56372 Jan 10 2003 /usr/lib/libz.1.1.3.dylib*
lrwxr-xr-x 1 mgh staff 16 Aug 1 18:04 /usr/lib/libz.1.dylib@ -> libz.1.1.3.dylib
lrwxr-xr-x 1 mgh staff 16 Aug 1 18:04 /usr/lib/libz.dylib@ -> libz.1.1.3.dylib

Both libz.dylib and libz.1.dylib point to libz.1.1.3.dylib.
You could change the links to point to your new libz.1.1.4.dylib
and see if that helps.

Or, install the new version in /usr/local/lib ! :-)