Originální popis anglicky:
pipe - create an interprocess channel
Návod, kniha: POSIX Programmer's Manual
#include <unistd.h>
int pipe(int
fildes[2]);
The
pipe() function shall create a pipe and place two file descriptors,
one each into the arguments
fildes[0] and
fildes[1], that refer
to the open file descriptions for the read and write ends of the pipe. Their
integer values shall be the two lowest available at the time of the
pipe() call. The O_NONBLOCK and FD_CLOEXEC flags shall be clear on both
file descriptors. (The
fcntl() function can be used to set both these
flags.)
Data can be written to the file descriptor
fildes[1] and read from the
file descriptor
fildes[0]. A read on the file descriptor
fildes[0] shall access data written to the file descriptor
fildes[1] on a first-in-first-out basis. It is unspecified whether
fildes[0] is also open for writing and whether
fildes[1] is also
open for reading.
A process has the pipe open for reading (correspondingly writing) if it has a
file descriptor open that refers to the read end,
fildes[0] (write end,
fildes[1]).
Upon successful completion,
pipe() shall mark for update the
st_atime,
st_ctime, and
st_mtime fields of the pipe.
Upon successful completion, 0 shall be returned; otherwise, -1 shall be returned
and
errno set to indicate the error.
The
pipe() function shall fail if:
- EMFILE
- More than {OPEN_MAX} minus two 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.
The following sections are informative.
None.
None.
The wording carefully avoids using the verb "to open" in order to
avoid any implication of use of
open(); see also
write() .
None.
fcntl() ,
read() ,
write() , the Base Definitions volume of
IEEE Std 1003.1-2001,
<fcntl.h>,
<unistd.h>
Portions of this text are reprinted and reproduced in electronic form from IEEE
Std 1003.1, 2003 Edition, Standard for Information Technology -- Portable
Operating System Interface (POSIX), The Open Group Base Specifications Issue
6, Copyright (C) 2001-2003 by the Institute of Electrical and Electronics
Engineers, Inc and The Open Group. In the event of any discrepancy between
this version and the original IEEE and The Open Group Standard, the original
IEEE and The Open Group Standard is the referee document. The original
Standard can be obtained online at http://www.opengroup.org/unix/online.html
.
