Create a file named "echo.ipc" to contain the IPC interface definition. It should look like this:

---
service: echo
domain: IPC_DOMAIN_USER
functions:
  echo:
    id: 1
    prototype: int echo(int *response, int request)
    on_error: NULL

Run ipcc to compile the interface definition file into C code.

$ ipcc echo.ipc

This will generate three files: a skeleton, a stub, and a Makefile fragment.