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Full Discussion: Non-blocking pipe
Top Forums Shell Programming and Scripting Non-blocking pipe Post 302285795 by cdlaforc on Monday 9th of February 2009 04:22:32 PM
Old 02-09-2009
Non-blocking pipe

Hello,
Would this be an acceptable way of creating a non-blocking pipe.
Basically I want to create kind of a server client arch.
This code would be in the server, and I don't want to have to wait for
clients to read before moving on to the next client. One problem I
can see is if a client leaves/dies and never reads from the pipe(but I
could have some trap/cleanup stuff in the clients for that).

# assigning fd 3 to the pipe
echo "exec 3>myfifo && echo 'a' >&3 && echo 'b' >&3 && echo 'c' >&3 &&
exec 3>&-" | at now



Chris.

Last edited by Neo; 02-09-2009 at 05:25 PM.. Reason: removed self promoting link of new member
 

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PIPE(2) 							System Calls Manual							   PIPE(2)

NAME
pipe - create an interprocess channel SYNOPSIS
pipe(fildes) int fildes[2]; DESCRIPTION
The pipe system call creates an I/O mechanism called a pipe. The file descriptors returned can be used in read and write operations. When the pipe is written using the descriptor fildes[1] up to 4096 bytes of data are buffered before the writing process is suspended. A read using the descriptor fildes[0] will pick up the data. Writes with a count of 4096 bytes or less are atomic; no other process can inter- sperse data. It is assumed that after the pipe has been set up, two (or more) cooperating processes (created by subsequent fork calls) will pass data through the pipe with read and write calls. The Shell has a syntax to set up a linear array of processes connected by pipes. Read calls on an empty pipe (no buffered data) with only one end (all write file descriptors closed) returns an end-of-file. SEE ALSO
sh(1), read(2), write(2), fork(2) DIAGNOSTICS
The function value zero is returned if the pipe was created; -1 if too many files are already open. A signal is generated if a write on a pipe with only one end is attempted. BUGS
Should more than 4096 bytes be necessary in any pipe among a loop of processes, deadlock will occur. ASSEMBLER
(pipe = 42.) sys pipe (read file descriptor in r0) (write file descriptor in r1) PIPE(2)
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