1PIPE(2)                       System Calls Manual                      PIPE(2)
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NAME

6       pipe - create an interprocess channel
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SYNOPSIS

9       pipe(fildes)
10       int fildes[2];
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DESCRIPTION

13       The  pipe system call creates an I/O mechanism called a pipe.  The file
14       descriptors returned can be used in read and  write  operations.   When
15       the  pipe is written using the descriptor fildes[1] up to 4096 bytes of
16       data are buffered before the writing  process  is  suspended.   A  read
17       using  the  descriptor  fildes[0] will pick up the data.  Writes with a
18       count of 4096 bytes or less are atomic; no  other  process  can  inter‐
19       sperse data.
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21       It  is assumed that after the pipe has been set up, two (or more) coop‐
22       erating processes (created by subsequent fork  calls)  will  pass  data
23       through the pipe with read and write calls.
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25       The  Shell has a syntax to set up a linear array of processes connected
26       by pipes.
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28       Read calls on an empty pipe (no buffered data) with only one  end  (all
29       write file descriptors closed) returns an end-of-file.
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SEE ALSO

32       sh(1), read(2), write(2), fork(2)
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DIAGNOSTICS

35       The  function value zero is returned if the pipe was created; -1 if too
36       many files are already open.  A signal is generated if  a  write  on  a
37       pipe with only one end is attempted.
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BUGS

40       Should  more  than  4096 bytes be necessary in any pipe among a loop of
41       processes, deadlock will occur.
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ASSEMBLER

44       (pipe = 42.)
45       sys pipe
46       (read file descriptor in r0)
47       (write file descriptor in r1)
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51                                                                       PIPE(2)