minix/lib/libc/sys/mkfifo.2

.\"	$NetBSD: mkfifo.2,v 1.27 2013/10/15 11:43:21 njoly Exp $
.\"
.\" Copyright (c) 1990, 1991, 1993
.\"	The Regents of the University of California.  All rights reserved.
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\" 1. Redistributions of source code must retain the above copyright
.\"    notice, this list of conditions and the following disclaimer.
.\" 2. Redistributions in binary form must reproduce the above copyright
.\"    notice, this list of conditions and the following disclaimer in the
.\"    documentation and/or other materials provided with the distribution.
.\" 3. Neither the name of the University nor the names of its contributors
.\"    may be used to endorse or promote products derived from this software
.\"    without specific prior written permission.
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
.\" ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
.\" SUCH DAMAGE.
.\"
.\"	@(#)mkfifo.2	8.1 (Berkeley) 6/4/93
.\"
.Dd July 29, 2013
.Dt MKFIFO 2
.Os
.Sh NAME
.Nm mkfifo ,
.Nm mkfifoat
.Nd make a fifo file
.Sh LIBRARY
.Lb libc
.Sh SYNOPSIS
.In sys/stat.h
.Ft int
.Fn mkfifo "const char *path" "mode_t mode"
.In sys/stat.h
.In fcntl.h
.Ft int
.Fn mkfifoat "int fd" "const char *path" "mode_t mode"
.Sh DESCRIPTION
.Fn mkfifo
creates a new fifo file with name
.Fa path .
The access permissions are
specified by
.Fa mode
and restricted by the
.Xr umask 2
of the calling process.
.Pp
.Fn mkfifoat
works the same way as
.Fn mkfifo
except if
.Fa path
is relative.
In that case, it is looked up from a directory whose file
descriptor was passed as
.Fa fd .
Search permission is required on this directory.
.\"    (These alternatives await a decision about the semantics of O_SEARCH)
.\" Search permission is required on this directory
.\" except if
.\" .Fa fd
.\" was opened with the
.\" .Dv O_SEARCH
.\" flag.
.\"    - or -
.\" This file descriptor must have been opened with the
.\" .Dv O_SEARCH
.\" flag.
.Fa fd
can be set to
.Dv AT_FDCWD
in order to specify the current directory.
.Pp
The fifo's owner ID is set to the process's effective user ID.
The fifo's group ID is set to that of the parent directory in
which it is created.
.Sh RETURN VALUES
.Rv -std mkfifo mkfifoat
.Sh ERRORS
.Fn mkfifo
and
.Fn mkfifoat
will fail and no fifo will be created if:
.Bl -tag -width Er
.It Bq Er EACCES
Search permission is denied for a component of the path prefix.
.It Bq Er EDQUOT
The directory in which the entry for the new fifo
is being placed cannot be extended because the
user's quota of disk blocks on the file system
containing the directory has been exhausted.
Or, the user's quota of inodes on the file system on
which the fifo is being created has been exhausted.
.It Bq Er EEXIST
The named file exists.
.It Bq Er EFAULT
.Fa path
points outside the process's allocated address space.
.It Bq Er EIO
An
.Tn I/O
error occurred while making the directory entry or allocating the inode.
Or, an
.Tn I/O
error occurred while reading from or writing to the file system.
.It Bq Er ELOOP
Too many symbolic links were encountered in translating the pathname.
.It Bq Er ENAMETOOLONG
A component of a pathname exceeded
.Brq Dv NAME_MAX
characters, or an entire path name exceeded
.Brq Dv PATH_MAX
characters.
.It Bq Er ENOENT
A component of the path prefix does not exist.
.It Bq Er ENOSPC
The directory in which the entry for the new fifo is being placed
cannot be extended because there is no space left on the file
system containing the directory.
Or, there are no free inodes on the file system on which the
fifo is being created.
.It Bq Er ENOTDIR
A component of the path prefix is not a directory.
.It Bq Er EOPNOTSUPP
The kernel has not been configured to support fifo's.
.It Bq Er EROFS
The named file resides on a read-only file system.
.El
.Pp
In addition,
.Fn mkfifoat
will fail if:
.Bl -tag -width Er
.It Bq Er EBADF
.Fa path
does not specify an absolute path and
.Fa fd
is neither
.Dv AT_FDCWD
nor a valid file descriptor open for reading or searching.
.It Bq Er ENOTDIR
.Fa path
is not an absolute path and
.Fa fd
is a file descriptor associated with a non-directory file.
.El
.Sh SEE ALSO
.Xr chmod 2 ,
.Xr stat 2 ,
.Xr umask 2
.Sh STANDARDS
The
.Nm mkfifo
function call conforms to
.St -p1003.1-90 .
.Fn mkfifoat
conforms to
.St -p1003.1-2008 .