mirror of https://github.com/mkerrisk/man-pages
112 lines
3.5 KiB
Groff
112 lines
3.5 KiB
Groff
.\" Hey Emacs! This file is -*- nroff -*- source.
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.\"
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.\" This manpage is Copyright (C) 1995 James R. Van Zandt <jrv@vanzandt.mv.com>
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.\"
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.\" Permission is granted to make and distribute verbatim copies of this
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.\" manual provided the copyright notice and this permission notice are
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.\" preserved on all copies.
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.\"
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.\" Permission is granted to copy and distribute modified versions of this
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.\" manual under the conditions for verbatim copying, provided that the
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.\" entire resulting derived work is distributed under the terms of a
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.\" permission notice identical to this one.
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.\"
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.\" Since the Linux kernel and libraries are constantly changing, this
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.\" manual page may be incorrect or out-of-date. The author(s) assume no
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.\" responsibility for errors or omissions, or for damages resulting from
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.\" the use of the information contained herein. The author(s) may not
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.\" have taken the same level of care in the production of this manual,
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.\" which is licensed free of charge, as they might when working
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.\" professionally.
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.\"
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.\" Formatted or processed versions of this manual, if unaccompanied by
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.\" the source, must acknowledge the copyright and authors of this work.
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.\"
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.\" changed section from 2 to 3, aeb, 950919
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.\"
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.TH MKFIFO 3 2008-06-12 "GNU" "Linux Programmer's Manual"
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.SH NAME
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mkfifo \- make a FIFO special file (a named pipe)
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.SH SYNOPSIS
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.nf
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.B #include <sys/types.h>
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.B #include <sys/stat.h>
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.sp
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.BI "int mkfifo(const char *" pathname ", mode_t " mode );
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.fi
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.SH DESCRIPTION
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.BR mkfifo ()
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makes a FIFO special file with name \fIpathname\fP.
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\fImode\fP specifies the FIFO's permissions.
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It is modified by the
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process's \fBumask\fP in the usual way: the permissions of the created
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file are \fB(\fP\fImode\fP\fB & ~umask)\fP.
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.PP
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A FIFO special file is similar to a pipe, except that it is created
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in a different way.
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Instead of being an anonymous communications
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channel, a FIFO special file is entered into the file system by
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calling
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.BR mkfifo ().
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.PP
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Once you have created a FIFO special file in this way, any process can
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open it for reading or writing, in the same way as an ordinary file.
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However, it has to be open at both ends simultaneously before you can
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proceed to do any input or output operations on it.
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Opening a FIFO for reading normally blocks until some
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other process opens the same FIFO for writing, and vice versa.
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See
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.BR fifo (7)
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for non-blocking handling of FIFO special files.
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.SH "RETURN VALUE"
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On success
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.BR mkfifo ()
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returns 0.
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In the case of an error, \-1 is returned (in which case, \fIerrno\fP
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is set appropriately).
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.SH ERRORS
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.TP
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.B EACCES
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One of the directories in \fIpathname\fP did not allow search
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(execute) permission.
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.TP
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.B EEXIST
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\fIpathname\fP already exists.
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This includes the case where
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.I pathname
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is a symbolic link, dangling or not.
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.TP
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.B ENAMETOOLONG
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Either the total length of \fIpathname\fP is greater than
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\fBPATH_MAX\fP, or an individual filename component has a length
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greater than \fBNAME_MAX\fP.
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In the GNU system, there is no imposed
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limit on overall filename length, but some file systems may place
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limits on the length of a component.
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.TP
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.B ENOENT
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A directory component in \fIpathname\fP does not exist or is a
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dangling symbolic link.
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.TP
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.B ENOSPC
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The directory or file system has no room for the new file.
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.TP
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.B ENOTDIR
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A component used as a directory in \fIpathname\fP is not, in fact, a
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directory.
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.TP
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.B EROFS
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\fIpathname\fP refers to a read-only file system.
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.SH "CONFORMING TO"
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POSIX.1-2001.
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.SH "SEE ALSO"
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.BR mkfifo (1),
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.BR close (2),
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.BR open (2),
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.BR read (2),
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.BR stat (2),
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.BR umask (2),
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.BR write (2),
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.BR mkfifoat (3),
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.BR fifo (7)
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