27 Feb
2018
27 Feb
'18
11:04 a.m.
pipes in SCO UNIX 3.2V4.2,
It's long, long ago, so excuses for vagueness. I think the issue was
not pipe() perse, but the difference in functionality between 'pipe
filesystem' and streams pipes.
By using pipe() you create a FIFO pipe with certain limitations
(including 5120 write limit). When you open the streams device twice
and ioctl() two file descriptors together you have more flexibility.
Excuses for the possible confusion.
27 Feb
27 Feb
11:48 a.m.
New subject: EOF on pipes?
On Tue, 27 Feb 2018, Rudi Blom wrote:
By using pipe() you create a FIFO pipe with certain
limitations
(including 5120 write limit). When you open the streams device twice and
ioctl() two file descriptors together you have more flexibility.
There's always been a limit on the write until the reader got around to
it; that's why you had to take care to avoid deadlocks.
Heck, I fell into a deadlock the other day with Perl; I thought that "say
<$reader_pipe>" (to echo whatever was read) as a neat shortcut would
work... It deadlocked, because "<>" was evaluated in list context
(because of "say") and hence waited for the EOF that would never arrive so
that I could close the writer end.
--
Dave Horsfall DTM (VK2KFU) "Those who don't understand security will
suffer."
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