How do I install a shared library?
 

I just installed Slackware 12.0 on my laptop but during the installation process there was an error while installing 3 library files. I continued the installation hoping I wouldn't need the library files it had trouble with, but afterwards when I tried to start up xfce it couldn't do it because it said it was missing a library.

So... I re-downloaded the files that didn't get installed from the "l" package and I want to now how to install them on my system. I noticed that the files I need are .tgz files so can I just copy the files to the /lib directory and run a tar command on them?

For Slackware packages, you use "installpkg filename.tgz". Also run "ldconfig" afterwards (I'm not sure this is strictly necessary, but it doesn't hurt).

Compiling Librarys - different method
 

Probably as the post before this said you would better off with SlackPackage, but you could also compile the source.

I move the tar.gz / tar.bz2 / .tgz package to /usr
I then with mc untar the package with F2 drop down menu
there are two selectioins I usually use the upper selection
of uncompressing the tar ball
then change to the directory under /usr/ex-prog2-1.3.4/

I write a shell batch file and copy it after it works to a
install dir say /home/install or whatever

Generally the procedure most times is:
cd /usr/ex-prog2-1.3.4/
make clean (if compiles before - and won't hurt if it wasn't)
# ./bootstrap
# ./autogen
./configure
make
make check
make test
make install

this is it most times, however sometimes it doesn't work and I have to add ./bootstrap before ./configure

then there is ./autogen problems

and then also python install programs are different.
generally there is a INSTALL file in the directory giving the instructions.

And getting to the crux of the problem
to get shared librarys when not configured as the default (usually)

./configure --enable-shared --enable-static
also I have been adding --enable-gnu-ld , and hasn't hurt yet.

How do you know what is the default and what other options are available (think xmms plugins)?

type ./configure --help | more
review all the available options, sometimes you might get a idea to turn off options --disable-xxx

sometimes to get a library to compile right you need to
specify paths to libraries. --prefix=/usr/lib or such

I beleive you can specify
./configure --enable-shared & --enable-static at the same time.

Rule of thumb - most times you want 'shared'

and the make check and make test probably could be left out, I do it anyway and watch what scrolls by. If make check, for example isn't valid - all you get is a little error (that can be ignored)