how to adjust the PKG_CONFIG_PATH environment ?

[lxfg]

I just upgrade gtk+1.2 to 2.0 using gtk2-2.0.5-1gtk.i386.rpm .
when I use this command:
gcc hellow.c -o hellow `pkg-config --cflags --libs gdk+-2.0`
it said I should add the directory containing 'gdk+-2.0.pc' to the
PKG_CONFIG_PATH enviroment variable.
My question is :
where is PKG_CONFIG_PATH and how to adjust it?
do I need to create gdk+-2.0.pc?

[dfx]

It's an environment variable, and as such it's located in your environment. At a shell, you can type "set" to list all current variables. You can print the contents of a certain var with "echo $VARNAME". You can set a var with "export VAR=contents".

I don't know about gtk2 or pkg-config, but PKG_CONFIG_PATH sounds like a typical PATH var, meaning it's a colon seperated list of path names. You can add a path to it with "export PKG_CONFIG_PATH=$PKG_CONFIG_PATH:/some/new/path". You can do that in your profile to make it permanent.