Cross Platform C library for GUI Apps? [closed]

Free of charge, simple to learn/use, Cross Platform C library for GUI Apps? Am I looking for Qt?

Bonus question: Can I develop with the said library/toolkit on Mac then recompile on PC/Linux?

Super Bonus Question: Link to tutorial and/or download of said library.

The truth is that I'm in the process of catching up on the C family (coming from web development - XHTML/PHP/MySQL) to learn iPhone development.

I do understand that C is not C++ or ObjectiveC but I want to keep the learning curve as simple as possible. Not to get too off topic, but I am also on the lookout for good starter books and websites. I've found this so far.

I'm trying to kill many birds with one stone here. I don understand that there are platform specific extensions, but I will try to avoid those for porting purposes The idea is that I want to write the code on one machine and just compile thrice. (Mac/Win/Linux) If Objective C will compile on Windows and Linux as well as OS X then that's good. If I must use C++, that's also fine.

Solution 1:

If you are looking for a C++ library, then Qt basically does what you are looking for. If you want to stick to pure C, then Qt is not an option.

As a C framework you could use GTK+, it works on Linux, Windows and OS X.

Solution 2:

Take a look at the IUP Toolkit. It is written largely in C, and is also easily bound to Lua.

Solution 3:

To complete this post Allegro has to be here =)

http://www.talula.demon.co.uk/allegro/ Allegro Game Library, have many graphics functions and a basic GUI library

And an explicit gui (and very simple) Allegro based library

http://cgui.sourceforge.net/index.html

Both multi-platform