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)).
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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