On Thu, Jul 24, 2025 at 04:38:29AM +0300, Valery Ushakov wrote: > Out signal(3) man page screams at the reader with emphasis: > > Unlike previous signal facilities, the handler func() remains > installed after a signal has been delivered. > > This paragraph and its supposed importance is probably a bit opaque > for a modern reader. It has not been relevant in ... 35-40 years? It > refers to the historic behavior (v7, 4BSD), where signal disposition > was reset to SIG_DFL after a signal was handled. > > I think it's time we reword this and move it to HISTORY, but my memory > is hazy. It seems 4.1BSD was transitional, and 4.2BSD had new signals > as the default and introduced the above phrase in signal(3). > Feedback, clarifications and proposed new wording are appreciated.
I'm pretty sure 4.1BSD had the old behaviour and 4.2BSD introduced the SOUSIG flag to optionally re-enable it. (I vaguely remember that it may also have had another function which was later removed, although that may be incorrect.)
