Re: Building emacs errors: libraries present

[Alexis <flexibeast@gmail.com>]

Tory S. Anderson writes:

> Okay; I've succeeded finally in building by soft-linking all the 
> libraries it SHOULD have been finding into the main 
> directories. I'm not sure why it cannot use libpng 16 and 
> instead requires 15. E.g. I did this:
> 
>     sudo ln -s /anaconda/lib/libpng15.so /usr/lib64/
> 
> Taking care of any non-found files that way solved all 
> problems. 
>
> ldconfig looks interesting, but I don't seem to have a manpage 
> on it. Unfortunately, it didn't solve the issue. Soft links 
> seemed to do the trick for me.

Very odd that your system doesn't have a manpage for ldconfig(8)! 
Here's the opening paragraph of that man page on my system:

"ldconfig creates, updates, and removes the necessary links and 
cache (for use by the run-time linker, ld.so) to the most recent 
shared libraries found in the directories specified on the command 
line, in the file /etc/ld.so.conf, and in the trusted directories 
(/usr/lib and /lib).  ldconfig checks the header and file names of 
the libraries it encounters when determining which versions should 
have their links updated.  ldconfig ignores symbolic links when 
scanning for libraries."

Basically, when you install new shared libraries on your system, 
you need to run /sbin/ldconfig in order to refresh the cache of 
available shared libraries. As someone else has pointed out, the 
directories searched for libraries is specified in /etc/ld.so.conf 
and related files; if you install shared libraries outside of 
those paths, you'll need to add the new paths to /etc/ld.so.conf 
(or possibly some other file, depending on the system's setup).

How are you installing the extra libraries? Are you installing the 
relevant -devel packages from your distro's repos, or are you 
manually compiling and installing them yourself? If the latter, 
then you'll need, as noted elsewhere in this thread, to make sure 
they're being installed in a path specified by /etc/ld.so.conf, or 
modify the latter file appropriately.

Needing to create symbolic links manually, as you have done, 
should normally not be necessary.


Alexis.