Matt Benson wrote:
--- Steve Loughran <[EMAIL PROTECTED]> wrote:
[SNIP]
I see. It is a lot easier to delegate to the OS,
isnt it:
<exec executable="mkfifo" osfamily="unix">
<arg file="./pipe" />
</exec>
Well! I am ashamed to say I had never encountered the
mkfifo command. My only contact with "named pipes"
had been in O'Reilly's "Learning the bash shell" in
which the >(foo) and <(bar) constructs for piping
to/from processes are covered briefly. Named pipes
are mentioned, I assume because they are implicitly
created by this bash syntax.
I tried this:
<exec executable="mkfifo">
<arg file="myfifo" />
</exec>
<parallel>
<echo file="myfifo">
foo
bar
baz
etc
</echo>
<concat>
<fileset file="myfifo" />
</concat>
</parallel>
<delete file="myfifo" />
and everything works as expected on Unix. This also
works on cygwin EXCEPT that the <delete> does not fail
in Ant yet still fails to delete the pipe. But since
fifos would be implemented in god-only-knows-what-way
that is unsurprising. Cool.
well there you go, you have learned something new. I've been using named
pipes where needed since, what, 1988. they are the most wonderfully
minimal bit of IPC on the planet.
WinNT has named pipes for network shares, which are an explicit bit of
remote IPC; you use ::CreateNamedPipe to create them. The funny is they
arent just simple nodes in the filesystem, they live in a special
\\machine\pipe\ place:-
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/ipc/base/createnamedpipe.asp
I presume this is what cygwin is using, though I dont know how they map
them to files in the filesystem, that is a miracle of hackery.
As with most bits of unix (i.e. symlinks), it is a shame that the Nt
implementation isnt as seamless as the unix one. it means we can't
easily work with it to provide a portable pipe mechanism that the OS
handles. But if you can stick to unix, pipes make a good IPC mechanism.
And like I said, if you have a proper clustering OS, those pipes work
across machines in the cluster.
-steve
---------------------------------------------------------------------
To unsubscribe, e-mail: [EMAIL PROTECTED]
For additional commands, e-mail: [EMAIL PROTECTED]
