Multi-threading-- calling same function through different threads

Sir,
Can I call same function in the start routines of different Threads.
I have created two different threads....and wanna call same function from both threads....is it possible???
Also can I fork inside a thread???

Yes.

Yes. However each function may or may not be thread safe, you need to refer to the documentation for each function. Also understand "cancellation points".

Yes, but be aware of what is happening, what fork means in a multithreaded environment, and understand pthread_atfork().