How do people justify writing GUIs only for Mac and Windows? They could make just a single QT program which would work on Linux too.

... or wxWidgets/wxWindows, or GTK+, or use Java, Tcl/Tk,... Plethora of choices.

@firusvg yeah, Qt was just the first I could think of

@franga2000 Actually, I think that most people would have Qt as first choice. ;)

@firusvg afaik Qt looks the most native, even supports the weird mac-style tabs

Because:
1) They don't know _any_ of crossplatform framework
2) They don't _need_ to write and handle platform-related errors if they'd pop out == laziness or well.. not everyone writes click-me buttons, somewhere is low-level needed
3) Maybe they were forbidden to support other platform(s) for "security" reasons
4) Can't use that object on their neck properly

I'd bet most of them are the second category and a little bit of the first one, still you'll find the other two if you're unlucky enough.

Following this theory, they should just write web applications because they are supported on even more devices.

Or they just didn't want too? Maybe their mass market is what they are developing for. Why would they waste time doing something else when time=money?

@blauesocke not really. My logic was that you write 1 program that supports 3 platforms instead of 2 programs that support one each.

@ScribeOfGoD I assume that making 1 program would cost less than 2 separate ones (2 from-scratch guis). But I've never done either, that's why I was asking.

@franga2000 neither have I so it's just speculation :)

@ScribeOfGoD @franga2000 I've done something like that - made few utilities for company's internal usage using wxWidgets. Compiled for Windows, Linux and OSX almost without any problems (used a bit of C preprocessing, mostly because of file paths - \ vs. /)