Al salamo Alykom,
Hi folks, how are you doing..
The last few days I were so interested in knowing about GTK and brothers. but after I knew About, I decided not going that way, at least not on a wide range!
So, Let me tell you what I found:
1- GTK is a GUI Tool Kit (it stands for GIMP Tool Kit) for doing GUI applications in C.
2- GDK stands for GTK Drawing kit
3- GLib is a low-level library used by GTK that replaces many of libc functions. (libc is the C standard library on Linux).
so in libGlib you may find functions for basic type definitions, memory management, string manipulations and alike )
I find that GTK (and its brothers) are intend to provide some object oriented C like features.