hi,
I want to install the GNOME 2.6 tar ball packages,while "/configure" the pango-2.6.0 for installation this is the error message:
checking for glib -version >=2.4.0 ...no
configure error:GLIB 2.4.0 or better is required,the latest version of
GLIB is aviable from ftp://ftp.gtk.org
I have already installed the glib-2.4.0 and with 'locate glib-2.0.pc' this is the result 'usr/lib/pkgconfig/glib-2.0.pc' and run the ldconfig after it. plz help me.

I may be going out on a limb here but I'm guessing you didn't install glib-2.4 with
./configure --prefix=/usr
if you just used ./configure then the glib you installed will be in /usr/local . This is a good thing. If you had installed it --prefix=/usr it would have overwritten the glib-2.2 that was already installed and many of the things that are linked against it would now be broken. Like Gnome for instance. You'd be unable to continue installing Gnome-2.6 unless you drop down to the command prompt. I've installed Gnome at the command prompt many times, but I've never successfully installed it over an older version of Gnome. Oh, except for the time I built Garnome in my home folder. However, enough about me.
What you need to do is point towards the new packages you are installing. You need to rearrange you PKG_CONFIG_PATH so it points towards /usr/local/lib/pkgconfig before /usr/lib/pkgconfigshould fix that. Now you need to set a couple more variables to avoid some other problemsThat will write those variables to the hidden file .bashrc in your home folder. If you want to change or delete them open ~/.bashrc in a text editor like Gedit. I think you would be very wise to do all your compiling and installing in your home folder as then your system will be safe and you won't have to reinstall Red hat. If you do decide to play it safe, alter those variables to point to wherever you decide to install your things. Good luck.

This is the second time you've given this information and it is NOT true. Installing glib-2.4 would not overwrite glib-2.2 - the two would co-exist quite happily and no links would be broken.

In my /usr/lib directory I have the following two files:

libglib-2.0.so.0.200.3
libglib-2.0.so.0.400.0

the former is glib-2.2.3, the latter is glib-2.4.0. The only change on installing the later version is the symlink glib-2.0.so now points to the second file instead of the first.

If what you said were true then no one would ever upgrade libraries for fear of breaking links.

Good point, but though it may be true that you can install two versions of glib side by side, my experience of installing Gnome has been that two different versions will not coexist peacefully.

Then you're doing something wrong - my versions co-exist happily, including gnome. I believe the advice you're giving newbies along this line is misleading - it doesn't just hold true for glib either, you can install any set of libraries side by side and they will co-exist. Like I said, if that weren't the case then no one would ever update libraries.

hi,
Thanks to all help,glib-2.4.0 from tar ball was installed in /usr/
local/lib/pkgconfig and the old version from rpm was in /usr/lib/
pkgconfig,the symlink didn't work forme,so i remove the old version
from /usr/lib/pkgconfig and installed it again with the prefix of './
configure --prefix=/usr/' and then the pango-1.4.0 was successfully
installed.