PIPE(2) PIPE(2)
NAME
pipe - create an interprocess channel
SYNOPSIS
#include <u.h>
#include <libc.h>
int pipe(int fd[2])
DESCRIPTION
Pipe creates a buffered channel for interprocess I/O commu-
nication. Two file descriptors are returned in fd. Data
written to fd[1] is available for reading from fd[0] and
data written to fd[0] is available for reading from fd[1].
After the pipe has been established, cooperating processes
created by subsequent fork(2) calls may pass data through
the pipe with read and write calls. The bytes placed on a
pipe by one write are contiguous even if many processes are
writing. Write boundaries are preserved: each read termi-
nates when the read buffer is full or after reading the last
byte of a write, whichever comes first.
The number of bytes available to a read(2) is reported in
the Length field returned by fstat or dirfstat on a pipe
(see stat(2)).
The limit of data bytes in the pipe's buffer can be set by
fwstat or dirfwstat on either of the pipe's descriptors.
When all the data has been read from a pipe and the writer
has closed the pipe or exited, read(2) will return 0 bytes.
Writes to a pipe with no reader will generate a note sys:
write on closed pipe.
SOURCE
/sys/src/libc/9syscall
SEE ALSO
intro(2), read(2), pipe(3)
DIAGNOSTICS
Sets errstr.
BUGS
If a read or a write of a pipe is interrupted, some unknown
number of bytes may have been transferred.
When a read from a pipe returns 0 bytes, it usually means
end of file but is indistinguishable from reading the result
of an explicit write of zero bytes.
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