Comment 2 for bug 73536

I believe SIGTERM can be synchronous or asynchronous. It's a signal that can by hanled by the target process, with the basic intent of: "Please terminate yourself, whatever that may entail". This is in contrast to SIGKILL, which cannot be handled by the target process: "Hey kernel, immediately terminate that process over there".

For example, IIRC, in the case of SIGTERM Apache returns from the signal, and then goes about shutting down it's child processes.