Which one is better gas or nasm?
Can I use gas to write windows application?

Not trying to discourage you from your incline towards assembly, but why would you want to write a GUI app in ASM? You'd be there for ever and a day...unless you have countless number of libraries at your use.

It would be much easier to write a GUI app in C (using GTK+) with some inline assembly.

As for which is better, not too sure.

i dont know if one is better or not. i prefer gas because that is what i learned with. the good thing is that once you know one form, the other is easy to pick up.

>Can I use gas to write windows application?
do you mean a win32 app, or a gui app?

if you mean win32, i dont know.. if you mean gui app, then sure.. there is no reason you cant.

i cant tell by your post if you are just beginning in assembly or not, if you are there is a great book that is freely available.. "Programming from the Ground Up" by Jonathan Bartlett. its an excellent resource (using gas) and well worth the $20 on amazon. it is also available for free in e print.

i couldn't get gdb to work properly with nasm(probably because of my own stupidity,or impatience) so I went with gas coz god I like to see what is going on