Re: Question Re: Piping and Redirection

[Pete Hall <pbhall@xxxxxxxxxxxxx>]

At 07:27 11/20/2002, Hans Boldt wrote:
> In Unix,
> commands use the predefined streams stdin, stdout, and stderr, all
> of which can be redirected and piped (largely) without the command
> being aware of the redirection.
There are OpnStdIn() (opens fildes[0]) and OpnStdOut() (opens fildes[1])
functions in the IS-Toolkit Unix service program. Could the pipe() method
in QP0LLIB1, along with these two functions be used to provide this
capability? The documentation for pipe() says:

Data can be written to the file descriptor fildes[1] and read from file
descriptor fildes[0]. A read on the file descriptor fildes[0] will access
data written to the file descriptor fildes[1] on a first-in-first-out
basis. File descriptor fildes[0] is open for reading only. File descriptor
fildes[1] is open for writing only.

As an aside, I think pipe() has nothing to do with the format of the data
in the database. It's the (generally printable) output of one program being
used as the input for another. It would be possible to implement this
capability with a data or message queue if it doesn't already exist.


Pete Hall
pbhall@ameritech.net
http://www.pbhall.us/