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mkfifo(P) mkfifo(P)
NAME
mkfifo - make FIFO special files
SYNOPSIS
mkfifo [-m mode] file...
DESCRIPTION
The mkfifo utility shall create the FIFO special files
specified by the operands, in the order specified.
For each file operand, the mkfifo utility shall perform
actions equivalent to the mkfifo() function defined in
the System Interfaces volume of IEEE Std 1003.1-2001,
called with the following arguments:
The file operand is used as the path argument.
The value of the bitwise-inclusive OR of S_IRUSR,
S_IWUSR, S_IRGRP, S_IWGRP, S_IROTH, and S_IWOTH is used
as the mode argument. (If the -m option is specified,
the value of the mkfifo() mode argument is unspecified,
but the FIFO shall at no time have permissions less
restrictive than the -m mode option-argument.)
OPTIONS
The mkfifo utility shall conform to the Base Definitions
volume of IEEE Std 1003.1-2001, Section 12.2, Utility
Syntax Guidelines.
The following option shall be supported:
-m mode
Set the file permission bits of the newly-created
FIFO to the specified mode value. The mode
option-argument shall be the same as the mode op-
erand defined for the chmod utility. In the sym-
bolic_mode strings, the op characters '+' and '-'
shall be interpreted relative to an assumed ini-
tial mode of a= rw.
OPERANDS
The following operand shall be supported:
file A pathname of the FIFO special file to be cre-
ated.
STDIN
Not used.
INPUT FILES
None.
ENVIRONMENT VARIABLES
The following environment variables shall affect the
execution of mkfifo:
LANG Provide a default value for the internationaliza-
tion variables that are unset or null. (See the
Base Definitions volume of IEEE Std 1003.1-2001,
Section 8.2, Internationalization Variables for
the precedence of internationalization variables
used to determine the values of locale
categories.)
LC_ALL If set to a non-empty string value, override the
values of all the other internationalization
variables.
LC_CTYPE
Determine the locale for the interpretation of
sequences of bytes of text data as characters
(for example, single-byte as opposed to multi-
byte characters in arguments).
LC_MESSAGES
Determine the locale that should be used to
affect the format and contents of diagnostic mes-
sages written to standard error.
NLSPATH
Determine the location of message catalogs for
the processing of LC_MESSAGES .
ASYNCHRONOUS EVENTS
Default.
STDOUT
Not used.
STDERR
The standard error shall be used only for diagnostic
messages.
OUTPUT FILES
None.
EXTENDED DESCRIPTION
None.
EXIT STATUS
The following exit values shall be returned:
0 All the specified FIFO special files were created
successfully.
>0 An error occurred.
CONSEQUENCES OF ERRORS
Default.
The following sections are informative.
APPLICATION USAGE
None.
EXAMPLES
None.
RATIONALE
This utility was added to permit shell applications to
create FIFO special files.
The -m option was added to control the file mode, for
consistency with the similar functionality provided by
the mkdir utility.
Early proposals included a -p option similar to the
mkdir -p option that created intermediate directories
leading up to the FIFO specified by the final component.
This was removed because it is not commonly needed and
is not common practice with similar utilities.
The functionality of mkfifo is described substantially
through a reference to the mkfifo() function in the Sys-
tem Interfaces volume of IEEE Std 1003.1-2001. For exam-
ple, by default, the mode of the FIFO file is affected
by the file mode creation mask in accordance with the
specified behavior of the mkfifo() function. In this
way, there is less duplication of effort required for
describing details of the file creation.
FUTURE DIRECTIONS
None.
SEE ALSO
chmod() , umask() , the System Interfaces volume of
IEEE Std 1003.1-2001, mkfifo()
COPYRIGHT
Portions of this text are reprinted and reproduced in
electronic form from IEEE Std 1003.1, 2003 Edition,
Standard for Information Technology -- Portable Operat-
ing System Interface (POSIX), The Open Group Base Speci-
fications Issue 6, Copyright (C) 2001-2003 by the Insti-
tute 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.open-
group.org/unix/online.html .
POSIX 2003 mkfifo(P)
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