c - Interprocess communication on UNIX -

I have to implement some mechanisms in C on Solaris 9 SPARC to allow for interprese transmission.

In short, I have to implement a multilevel program where the thread's father receives one signal once, or whatever you want, to trigger a set of threads that encrypts the files Are in charge of doing so.

i Can not use some TCP socket solution to communicate with this program.

I was considering using the system signal (and the process triggered by kill -s signal PID) or by the domain Unix socket.

> What do you think? Can you recommend some other solutions to me?

Other Solutions: Shared Memory Segment, Pipelining, Unix Socket (O, They Are not TCP :)) , ...