On Sat, Aug 01, 2020 at 05:40:07PM +0100, Jason McIntyre wrote: > i'm worried that you're blurring the distinction between asynchronous > and co-process for the reader. i think that's relevant because, as you > say, a page like sh(1) does not document co-processes, whereas ksh(1) > does. You raise a valid point.
> as i understand it, ksh explains co-processes as a type of asynchronous > process. and the setting of "!" is applicable to both. is that right? Correct. Both background jobs (`&') and co-processes (`|&') are asynchronous and co-processes are background jobs by definition. What makes co-processes different is a two-way pipe between them and the shell, i.e. you can read and write in both directions. > so could your text be better written as: > > Process ID of the last background or asynchronous process started. > If no processes have been started, the parameter is not set. > > this would catch the setting of "!" for both async and co-process, > without making the text read like the two are identical. > > if your concern is that you need to be able to /co-process, then i'd > rewrite the text to not blur the two: > > Process ID of the last background, co-process, or asynchronous > process started. > > but i dislike that, because it means the text suffers because of an > arbitrary request to make a specific search work. Indeed, I'd like to have `/co-process<enter>' show it. > i guess we could add a note to the "Some notes concerning co-processes" > section if it needs more clarity. I don't think this is needed. Background jobs as well as co-processes are async and background jobs or rather `&' is documented as "asynchronous command" in other places of the manual, so how about this? Index: ksh.1 =================================================================== RCS file: /cvs/src/bin/ksh/ksh.1,v retrieving revision 1.209 diff -u -p -r1.209 ksh.1 --- ksh.1 7 Jul 2020 10:33:58 -0000 1.209 +++ ksh.1 1 Aug 2020 16:59:10 -0000 @@ -1247,8 +1247,8 @@ The following special parameters are imp set directly using assignments: .Bl -tag -width "1 ... 9" .It Ev \&! -Process ID of the last background process started. -If no background processes have been started, the parameter is not set. +Process ID of the last background process or co-process started. +If no asynchronous processes have been started, the parameter is not set. .It Ev \&# The number of positional parameters ($1, $2, etc.). .It Ev \&$
