Re: SIGPIPE (Re: ZSH history not saved anymore)

[Peter Stephenson <p.stephenson@samsung.com>]

On Sun, 28 Sep 2014 13:16:27 -0700
Bart Schaefer <schaefer@brasslantern.com> wrote:
> On Sep 28,  7:18pm, Peter Stephenson wrote:
> }
> } So in the first case I presume we're exiting (silently) on SIGPIPE.  That
> } should be just a question of checking if SIGPIPE is trapped and if it isn't
> } setting the handler to the default in entersubsh().  There's some partial
> } prior art for this.
> 
> It gets a little stranger - this is again before the patch:
> 
> torch% TRAPPIPE() { : }                                              
> torch% (sleep 5; echo hello; print -u2 $sysparams[pid] continued after PIPE) |
> (exit)
> TRAPPIPE: write error: broken pipe
> echo: write error: broken pipe
> zsh: write error: broken pipe
> 3579 continued after PIPE
> 
> 
> Why did TRAPPIPE() receive a SIGPIPE?  And then:

I think we're looking at this in execcmd() or similar chunks.

		/* It's a builtin */
		if (forked)
		    closem(FDT_INTERNAL);
		lastval = execbuiltin(args, (Builtin) hn);
		fflush(stdout);
		if (save[1] == -2) {
		    if (ferror(stdout)) {
			zwarn("write error: %e", errno);
			clearerr(stdout);
		    }
		} else
		    clearerr(stdout);

so it doesn't necessarily mean there's a signal, just that there's a
broken pipe.  Maybe the fflush() is enough to trigger setting errno
again if it failed to write the first time?

pws