ipc - System V IPC system calls
int ipc(unsigned int call, int first, int second ", int " third , void *ptr, long fifth);
ipc() is a common kernel entry point for the System V IPC calls for messages, semaphores, and shared memory. call determines which IPC function to invoke; the other arguments are passed through to the appropriate call.
User-space programs should call the appropriate functions by their usual names. Only standard library implementors and kernel hackers need to know about ipc().
ipc() is Linux-specific, and should not be used in programs intended to be portable.