pipe(2) System Calls pipe(2)NAMEpipe - create an interprocess channel
SYNOPSIS
#include <unistd.h>
int pipe(int fildes[2]);
DESCRIPTION
The pipe() function creates an I/O mechanism called a pipe and returns
two file descriptors, fildes[0] and fildes[1]. The files associated
with fildes[0] and fildes[1] are streams and are both opened for read‐
ing and writing. The O_NDELAY, O_NONBLOCK, and FD_CLOEXEC flags are
cleared on both file descriptors. The fcntl(2) function can be used to
set these flags.
A read from fildes[0] accesses the data written to fildes[1] on a
first-in-first-out (FIFO) basis and a read from fildes[1] accesses the
data written to fildes[0] also on a FIFO basis.
Upon successful completion pipe() marks for update the st_atime,
st_ctime, and st_mtime fields of the pipe.
RETURN VALUES
Upon successful completion, 0 is returned. Otherwise, −1 is returned
and errno is set to indicate the error.
ERRORS
The pipe() function will fail if:
EMFILE More than {OPEN_MAX} file descriptors are already in use by
this process.
ENFILE The number of simultaneously open files in the system would
exceed a system-imposed limit.
ATTRIBUTES
See attributes(5) for descriptions of the following attributes:
┌─────────────────────────────┬─────────────────────────────┐
│ ATTRIBUTE TYPE │ ATTRIBUTE VALUE │
├─────────────────────────────┼─────────────────────────────┤
│Interface Stability │Committed │
├─────────────────────────────┼─────────────────────────────┤
│MT-Level │Async-Signal-Safe │
├─────────────────────────────┼─────────────────────────────┤
│Standard │See standards(5). │
└─────────────────────────────┴─────────────────────────────┘
SEE ALSOsh(1), fcntl(2), fstat(2), getmsg(2), poll(2), putmsg(2), read(2),
write(2), attributes(5), standards(5), streamio(7I)NOTES
Since a pipe is bi-directional, there are two separate flows of data.
Therefore, the size (st_size) returned by a call to fstat(2) with argu‐
ment fildes[0] or fildes[1] is the number of bytes available for read‐
ing from fildes[0] or fildes[1] respectively. Previously, the size
(st_size) returned by a call to fstat() with argument fildes[1] (the
write-end) was the number of bytes available for reading from fildes[0]
(the read-end).
SunOS 5.11 23 Apr 2002 pipe(2)
