Name
mkfifo, mkfifoat — make a FIFO special file (a named pipe)
Synopsis
#include <sys/types.h> #include <sys/stat.h>
int
mkfifo( |
const char *pathname, |
mode_t mode); |
#include <fcntl.h> /* Definition of AT_* constants */ #include <sys/stat.h>
int
mkfifoat( |
int dirfd, |
| const char *pathname, | |
mode_t mode); |
![[Note]](../stylesheet/note.png) |
Note | |||||
|---|---|---|---|---|---|---|
|
DESCRIPTION
mkfifo() makes a FIFO
special file with name pathname. mode specifies the FIFO's
permissions. It is modified by the process's umask in the usual way: the permissions of
the created file are (mode & ~umask).
A FIFO special file is similar to a pipe, except that it
is created in a different way. Instead of being an anonymous
communications channel, a FIFO special file is entered into
the filesystem by calling mkfifo().
Once you have created a FIFO special file in this way, any process can open it for reading or writing, in the same way as an ordinary file. However, it has to be open at both ends simultaneously before you can proceed to do any input or output operations on it. Opening a FIFO for reading normally blocks until some other process opens the same FIFO for writing, and vice versa. See fifo(7) for nonblocking handling of FIFO special files.
mkfifoat()
The mkfifoat() function
operates in exactly the same way as mkfifo(), except for the differences
described here.
If the pathname given in pathname is relative, then it
is interpreted relative to the directory referred to by the
file descriptor dirfd (rather than relative
to the current working directory of the calling process, as
is done by mkfifo() for a
relative pathname).
If pathname is
relative and dirfd
is the special value AT_FDCWD, then pathname is interpreted
relative to the current working directory of the calling
process (like mkfifo()).
If pathname is
absolute, then dirfd is ignored.
RETURN VALUE
On success mkfifo() and
mkfifoat() return 0. In the
case of an error, −1 is returned (in which case,
errno is set appropriately).
ERRORS
- EACCES
-
One of the directories in
pathnamedid not allow search (execute) permission. - EDQUOT
-
The user's quota of disk blocks or inodes on the filesystem has been exhausted.
- EEXIST
-
pathnamealready exists. This includes the case wherepathnameis a symbolic link, dangling or not. - ENAMETOOLONG
-
Either the total length of
pathnameis greater thanPATH_MAX, or an individual filename component has a length greater thanNAME_MAX. In the GNU system, there is no imposed limit on overall filename length, but some filesystems may place limits on the length of a component. - ENOENT
-
A directory component in
pathnamedoes not exist or is a dangling symbolic link. - ENOSPC
-
The directory or filesystem has no room for the new file.
- ENOTDIR
-
A component used as a directory in
pathnameis not, in fact, a directory. - EROFS
-
pathnamerefers to a read-only filesystem.
The following additional errors can occur for mkfifoat():
- EBADF
-
dirfdis not a valid file descriptor. - ENOTDIR
-
pathnameis a relative path anddirfdis a file descriptor referring to a file other than a directory.
VERSIONS
mkfifoat() was added to
glibc in version 2.4. It is implemented using mknodat(2), available on
Linux since kernel 2.6.16.
ATTRIBUTES
For an explanation of the terms used in this section, see attributes(7).
| Interface | Attribute | Value |
mkfifo(), mkfifoat() |
Thread safety | MT-Safe |
COLOPHON
This page is part of release 4.07 of the Linux man-pages project. A
description of the project, information about reporting bugs,
and the latest version of this page, can be found at
https://www.kernel.org/doc/man−pages/.
|
This manpage is Copyright (C) 1995 James R. Van Zandt <jrvvanzandt.mv.com> and Copyright (C) 2006, 2014 Michael Kerrisk %%%LICENSE_START(VERBATIM) Permission is granted to make and distribute verbatim copies of this manual provided the copyright notice and this permission notice are preserved on all copies. Permission is granted to copy and distribute modified versions of this manual under the conditions for verbatim copying, provided that the entire resulting derived work is distributed under the terms of a permission notice identical to this one. Since the Linux kernel and libraries are constantly changing, this manual page may be incorrect or out-of-date. The author(s) assume no responsibility for errors or omissions, or for damages resulting from the use of the information contained herein. The author(s) may not have taken the same level of care in the production of this manual, which is licensed free of charge, as they might when working professionally. Formatted or processed versions of this manual, if unaccompanied by the source, must acknowledge the copyright and authors of this work. %%%LICENSE_END changed section from 2 to 3, aeb, 950919 |