Can UNIX pipe connections be compiled?

[Tom Christiansen]

>From the keyboard of uunet!bria!mike (Michael Stefanik):
:Unless I'm reading you wrong, you seem to think that pipes are some coded
:mechanism for communication between processes; it isn't.  An (anonymous)
:pipe is a temporary entity created in the filesystem by the kernel on
:behalf of two related processes that want to communicate.  

No, it's not.  On BSD systems, pipe(2) is implemented as a 
semi-disabled version of socketpair(2).  It's all IPC -- no
filesystem activity is involved.  All the work is not a Vax,
nor is it SysV.  

:It is useful 
:to think of a pipe as a regular file, in which one process is writing to on
:one end, and another process is reading from on the other end.
:
:Typically, a pipe can buffer up to about 5K of data flowing through the
4k on my system.
:pipe.  When the pipe "fills up", the writing process is blocked until
:the reading process reads from the pipe.  Similarly, the reading process
:will block on an empty pipe, until the writing process writes something.
:Should the reading process die and the writing process attempt to write
:on the pipe, a signal will be sent (SIGPIPE) to the offending writing
:process (which tells it that there is no longer anything out there to
:read from the pipe).  If this wasn't done, the writing process would deadlock
:when the pipe buffer filled, waiting for a reading process that no longer
:existed.

This is all true and useful information.  (As far as I know.)

:So, after this brief overview of piping, the answer is, no, you cannot
:"compile" pipes to increase the speed of reads and writes to the pipe.

But you can often rearrange your program so it doesn't shove the data
through a bunch of processes' address spaces.  A good example is the slow
old makewhatis script, which runs much faster when coded do to the work
entirely in one process.  

--tom
--
"Hey, did you hear Stallman has replaced /vmunix with /vmunix.el?  Now
 he can finally have the whole O/S built-in to his editor like he
 always wanted!" --me (Tom Christiansen <tchrist at convex.com>)