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POSIX says that "setting a trap for SIGKILL or SIGSTOP produces undefined results", but for signals it describes SIGKILL as "Kill (cannot be caught or ignored)"

by arp242 3y ago

POSIX says that "setting a trap for SIGKILL or SIGSTOP produces undefined results", but for signals it describes SIGKILL as "Kill (cannot be caught or ignored)". I'm guessing this is some relic from 80s Unix systems where SIGKILL behaved different, or perhaps just an inconsistency/oversight.

nerdponx 3y ago
I read that as undefined in terms of how the shell itself handles it, because the OS doesn't care.
- remram 3y ago
  I think it means that it is valid for OSes to return an error instead of doing nothing, if you attempt it.