I have an application written in C on Solaris that I have to port to Windows XP. I would like to know that what are the libraries availabe to achieve this task. Also what is the best GUI development tool for the same and what are the steps to follow to achieve this all.
Easiest way is to compile it under cygwin, and have it run in the Cygwin X server. If you port it to a cross-platform GUI toolkit like QT, then you can compile it natively for each platform. (Or maybe with mingw or even still cygwin on windows, if it does much besides being a GUI and needs POSIX library functions and system calls.)
What compiler did you use on Solaris? The suncc compiler or the GCC compiler? In the latter case, your first bet would be to compile under Cygwin and see what errors and library it finds missing and try to install them in your Cygwin installation. You can proceed incrementally this way.
If you compiled it with suncc, still you should try and compiler on Windows under Cygwin and see what libraries and incompatibilities it says missing.
After you have got it ported to Cygwin succesfully, you should then look to make it run on Windows bare, without Cygwin.
HTH, Amit