How Do C Cope with more than one mian()'s compiling task?

[lazyL]

Hey, all!

I am totally new in the world of C!
Recently, I got a bunch of C source codes of an application and need to find a way to read it.
I start from readme file, then some *.vcproj files, later on I read Makefile.nmake.
I do know that in order to read the codes, I need to find the main() first, and I got them easily (lucky~).
However, I found more than one main() which is reasonable, as a big application may have several *.exe files too.
But I do get confused, since I am not sure what is the actually "starting point" of all the codes.

Do someone know how this will be done by compiler, or some reccomended reading materials will be appreciated!

[cyberfish]

One program only has one main(), so if it has multiple main()'s, they must be the starting point of multiple programs (*.exe). They would be separate programs.

[lazyL]

One program only has one main(), so if it has multiple main()'s, they must be the starting point of multiple programs (*.exe). They would be separate programs.

UR right！
But most of the applications are sets of multiple programs, right?
When I start a *.exe, I may see a GUI panel with buttons by which I can call other programs
How does these programs cooperates with each other then?
Especially, in some cases there are no buttions, my guess is that programs may be called by Shell.
Is it a good guess then ?