Send data over Unix signals.

Unix provides signals, like SIGTERM and SIGSTOP which let two processes, or the kernel and the process commmunicate with each other. This form of IPC can be used to send any binary data, if both processes cooperate.

Please do not use this in production. There are many better ways to send data between processes, like pipes.

Usage

Use of this crate requires initialisation of the [SignalStream] object. This object can be used to write or read from the SignalStream of the other specified process. read() must always be called by a recieving process before any data is sent over the SignalStream, otherwise data may be incomplete or corrupted. See the documentation for read() for more details.

// Process 1
use signalstream::*;
let mut sigstream = SignalStream::new(pid2);
let mut buf = [0; 6];
sigstream.read(&mut buf);
println!("String: {}", from_utf8(&buf).unwrap());

// Process 2
let mut sigstream = SignalStream::new(pid1);
sigstream.write("Hello!".as_bytes());

Process 2 must begin execution after Process 1.

Notes

This crate uses the SIGUSR1, SIGUSR2 and SIGSTKFLT signals to transfer data and indicate EOF. Though unikely, if your program (or the other program) use these signals, unexpected behavior may occur. Additionally, if the other program does not use SignalStream, recieving these signals may cause it to terminate.