I've been working on a system program targeted for POSIX but I've run into the problem of not having access to sigqueue. Does Darwin/XNU have an alternative way of sending signals to another process? I've seen kill() but nothing else.
After reading the POSIX standard, I came to understand that kill had been extended to so that you can actually send any kind of signal that you specify and will not automatically cause the receiving application to terminate (unless you send SIGKILL).