This week's book giveaway is in the Mac OS forum. We're giving away four copies of a choice of "Take Control of Upgrading to Yosemite" or "Take Control of Automating Your Mac" and have Joe Kissell on-line! See this thread for details.
Hi Priyanka, if i have understood your question correctly you are asking about inter process communication.
Every process has its own address space, and threads inside it can share some data that is where we do synchronization, but two process doesn't share anything in common.
If you have to do it, you need OS level support like network, files, pipes, queues, RPC calls etc. Again this is not thread to thread communication.