[TCLCORE] Fwd: [Tcl-bugs] [Tcl Source Code] Commit by dkf - Make a few tests more resilient to differences in the semantics of pipes between operating systems.

[Alexandre F. <ale...@gm...>]

Hi Donal,

Can you please share some details ? First, which exotic OS exhibits the
problem ?
Though I admit I manage to keep a few parsecs clear from Windows these
days, in the past I have heavily depended on  pipes there, and never
encountered more than userland bugs (e.g. in the Tcl channel machinery).
But what you're saying here sounds like a kernel-side buffering that's
completely alien to me.


Note that the pipe buffering semantics can vary at the operating
system levelsubstantially; it is not safe to assume that a write
performed on the outputside of the pipe will appear instantly to the
input side. This is afundamental difference and Tcl cannot conceal it.
The overall stream semantics\fIare\fR compatible, so blocking reads
and writes will not see most of thedifferences, but the details of
what exactly gets written when are not. Thisis most likely to show up
when using pipelines for testing; care should betaken to ensure that
deadlocks do not occur and that potential short reads areallowed for.



---------- Forwarded message ----------
From: <aku...@sh...>
Date: Sun, Jul 24, 2016 at 2:45 PM
Subject: [Tcl-bugs] [Tcl Source Code] Commit by dkf - Make a few tests more
resilient to differences in the semantics of pipes between operating
systems.
To: tcl...@li...