Name

mkfifo — 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);

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 file system 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 non-blocking handling of FIFO special files.

RETURN VALUE

On success mkfifo() returns 0. In the case of an error, −1 is returned (in which case, errno is set appropriately).

ERRORS

EACCES

One of the directories in pathname did not allow search (execute) permission.

EEXIST

pathname already exists.

ENAMETOOLONG

Either the total length of pathname is greater than PATH_MAX, or an individual filename component has a length greater than NAME_MAX. In the GNU system, there is no imposed limit on overall filename length, but some file systems may place limits on the length of a component.

ENOENT

A directory component in pathname does 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 pathname is not, in fact, a directory.

EROFS

pathname refers to a read-only filesystem.

CONFORMING TO

POSIX.1-2001.

SEE ALSO

mkfifo(1), close(2), open(2), read(2), stat(2), umask(2), write(2), mkfifoat(3), fifo(7)

COLOPHON

This page is part of release 2.79 of the Linux man-pages project. A description of the project, and information about reporting bugs, can be found at http://www.kernel.org/doc/man-pages/.


This manpage is Copyright (C) 1995 James R. Van Zandt <jrvvanzandt.mv.com>

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.

changed section from 2 to 3, aeb, 950919