On Thu, May 16, 2013 at 6:46 PM, David Korn <[email protected]> wrote: > cc: [email protected] > Subject: Re: [ast-users] ksh exec'ing into last line of a script--different > in u & u+? > -------- > >> I have a script which, in its last line, calls another command. When I run >> it wi >> th ksh93u 2011-02-08 as its !#, the ksh process appears to exec into the >> command >> --it disappears from ps, the command appears with the PID the shell >> previously h >> ad, etc. With ksh93u+ 2012-08-01, this doesn't happen--the command appears >> as a >> child process of the shell script. >> >> While this is not necessarily a problem, I'd like to understand the new >> behavior >> . Is it expected? Are there any circumstances under which ksh93u+ will exec >> inst >> ead of fork/exec? >> > This is an optimization that the shell uses to save a fork() for better > performance. > > There are a number of things that disable this optimization, for example > trap : EXIT > which sets an exit trap will prevent it.
AFAIK this optimization is widely known - but is it documented in ksh93(1)? Irek _______________________________________________ ast-users mailing list [email protected] http://lists.research.att.com/mailman/listinfo/ast-users
