HI I have around 200 subroutines (may be more) and I have compiled that program with windows. However, I need to recompile that code in LINUX platform. But whenever I try to compile that in linux I always get error. The common error I get is "undefined reference to main __". As a new user of linux platform I don't know what that means and how to fix it. This is the same code that runs on windows. 

Please help me asap. 

Thanks. 
Anjeep