Bug with two pipes to a process

chris.umcp-cs%udel-relay at sri-unix.UUCP chris.umcp-cs%udel-relay at sri-unix.UUCP
Tue Jun 7 07:42:08 AEST 1983


From:  Chris Torek <chris.umcp-cs at udel-relay>

	From: ihnp4!arizona!whm at ucb-vax

	... However, for some programs that produced a line of
	output that was not newline terminated, the data on the
	"last" line would never appear.  Two programs in point are
	ucbmail and ex.  ...  The problem only occurred when a
	write pipe was also open to the program.  All streams were
	unbuffered.  BTW-This was on 4.1bsd.

I don't know about ucbmail, but ex seems to have great troubles
when it's not connected to a terminal.  It wants to stty, and when
it fails, thinks that is some other error.  If I run "ex | cat -u"
I get "missing lhs" (!).  It may just be someone trying to get
around stdio (ex moves mountains to do this).

	I've since decided to use a more sophisticated IPC mechanism,
	such as mpx files or the new Berkeley IPC stuff, but I'm
	still curious about the bug.  Anybody have any ideas?

Probably someone didn't consider that you might want to use pipes.


					- Chris
					seismo!umcp-cs!chris
					chris.umcp-cs at UDel-Relay



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