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Re: C-z fg bg sees thru scripts to affect sleep
From: |
Sven Mascheck |
Subject: |
Re: C-z fg bg sees thru scripts to affect sleep |
Date: |
31 Oct 2001 17:30:02 +0100 |
User-agent: |
tin/1.4.5-20010409 ("One More Nightmare") (UNIX) (SunOS/5.8 (sun4u)) |
Chet Ramey <chet@nike.ins.cwru.edu> wrote:
> When you type ^Z, all processes in the shell script's process group get
> the signal. This includes the `sleep', which immediately terminates.
But to my best knowledge, *Linux* is the only system, where this happens ;-)
- there, sleep(3) calls nanosleep(2), but apparently it should not,
because this returns with EINTR on SIGCONT.
- sleep(1) doesn't look at the return value of sleep(3) (unslept time),
perhaps it should, but almost nobody does in this concern, anyway.
- One could also implement a sleep built-in, e.g. using alarm(2) instead
of nanosleep(2). ksh93(1) does so, btw.
I'd expect sleep(1)/(3) (when not running with realtime capabilities)
to *stop transparently* on SIGTSTP/SIGSTOP, i.e. to be more robust.
Debugging with ptrace(2) is also affected, btw. In reality, all this
might not be *that* important.
Sven
--
<http://www.uni-ulm.de/~s_smasch/various/nanosleep_linux/>