GNU/Linux man pages
Livre :
Expressions régulières,
Syntaxe et mise en oeuvre :
Unix |
Unix v6 |
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pipe(2) |
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pipe create an interprocess channel (pipe = 42.)
sys pipe
(read file descriptor in r0)
(write file descriptor in r1) pipe(fildes)
int fildes[2]; The 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 returned in r1 (resp. fildes[1]), up to 4096
bytes of data are buffered before the writing process is
suspended. A read using the descriptor returned in r0 (resp.
fildes[0]) will pick up the data. It is assumed that after
the pipe has been set up, two (or more) cooperating
processes (created by subsequent calls) will pass data
through the pipe with and 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) return an end-of-file.
Write calls under similar conditions generate a fatal signal
(signal (II)); if the signal is ignored, an error is
returned on the write. sh (I), read (II), write (II), fork
(II) The error bit (c-bit) is set if too many files are
already open. From C, a 1 returned value indicates an error.
A signal is generated if a write on a pipe with only one end
is attempted.
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pipe(2) | |