Windows to Unix

Hi,
Can u please tell me what are the guidelines to be followed when migrating a C++ application written in Windows to Unix. the application has used lots of threads.

Thanks in advance,
Santosh.

i have just writing simple apllication withouth useing os specific things like windows messaging things in windows or network interface it is not hard to compile it on unix. simply cause normal c++ apps which compile in visual c++ also compile in gcc. i tried some. just i have no expierence with c threads in linux just java and also that is to easy (nothing needs to be changed ;-p but wasn't java designed for that ).