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pipe(2) [v7 man page]

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)

Check Out this Related Man Page

PIPE(2) 						      BSD System Calls Manual							   PIPE(2)

NAME
pipe -- create descriptor pair for interprocess communication SYNOPSIS
#include <unistd.h> int pipe(int fildes[2]); DESCRIPTION
The pipe() function creates a pipe (an object that allows unidirectional data flow) and allocates a pair of file descriptors. The first descriptor connects to the read end of the pipe; the second connects to the write end. Data written to fildes[1] appears on (i.e., can be read from) fildes[0]. This allows the output of one program to be sent to another pro- gram: the source's standard output is set up to be the write end of the pipe; the sink's standard input is set up to be the read end of the pipe. The pipe itself persists until all of its associated descriptors are closed. A pipe whose read or write end has been closed is considered widowed. Writing on such a pipe causes the writing process to receive a SIGPIPE signal. Widowing a pipe is the only way to deliver end-of-file to a reader: after the reader consumes any buffered data, reading a widowed pipe returns a zero count. The generation of the SIGPIPE signal can be suppressed using the F_SETNOSIGPIPE fcntl command. RETURN VALUES
On successful creation of the pipe, zero is returned. Otherwise, a value of -1 is returned and the variable errno set to indicate the error. ERRORS
The pipe() call will fail if: [EFAULT] The fildes buffer is in an invalid area of the process's address space. [EMFILE] Too many descriptors are active. [ENFILE] The system file table is full. SEE ALSO
sh(1), fork(2), read(2), socketpair(2), fcntl(2), write(2) HISTORY
A pipe() function call appeared in Version 6 AT&T UNIX. 4th Berkeley Distribution February 17, 2011 4th Berkeley Distribution
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