On 09/07/2010 12:24 AM, Al wrote:
How does a program in Gentoo know, where to look for shared libraries?
The program doesn't know. But the runtime linker does. And those paths are
in /etc/ld.so.conf. This file gets updated automatically by portage when
needed.
But... sometimes the program also knows and can link against libraries long
after it has started up using a dlopen() call:
http://linux.die.net/man/3/dlopen
Thank you Nikos. I did read obout this in the Linux HOWTO:
http://www.faqs.org/docs/Linux-HOWTO/Program-Library-HOWTO.html#DL-LIBRARIES
But I was woundering if the /etc/ld.so.conf was only historical stuff.
O.K. is not it's up-to-date. Good to know this.
But it also writes that dlopen() is specific for Linux and Solaris.
There would be alternatives:
1.) The glib library
2.) libltdl, which is part of GNU libtool
Now I was woundering, which way would Gentoo choose or if that is not
package specific at all. Are you sure dlopen() is used as a general
approach on Gentoo?
Gentoo doesn't choose anything; it's up to the programs to decide how
they want to load libraries at runtime. It's like asking whether Gentoo
chooses to use Qt or Gtk to run Firefox; well, since Firefox is a Gtk
application and is making calls to Gtk functions, Gentoo doesn't have a
say about it.
