MKFIFO(P) POSIX Programmer's Manual MKFIFO(P)NAMEmkfifo - make FIFO special files
SYNOPSISmkfifo [-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 equiva‐
lent to the mkfifo() function defined in the System Interfaces volume
of IEEE Std 1003.1-2001, called with the following arguments:
1. The file operand is used as the path argument.
2. 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 operand defined for the chmod utility. In the sym‐
bolic_mode strings, the op characters '+' and '-' shall be
interpreted relative to an assumed initial mode of a= rw.
OPERANDS
The following operand shall be supported:
file A pathname of the FIFO special file to be created.
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 internationalization variables
that are unset or null. (See the Base Definitions volume of
IEEE Std 1003.1-2001, Section 8.2, Internationalization Vari‐
ables 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 messages 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 spe‐
cial 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 refer‐
ence to the mkfifo() function in the System Interfaces volume of
IEEE Std 1003.1-2001. For example, 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 cre‐
ation.
FUTURE DIRECTIONS
None.
SEE ALSOchmod() , 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 Operating System Interface (POSIX), The Open Group Base
Specifications Issue 6, Copyright (C) 2001-2003 by the Institute 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.opengroup.org/unix/online.html .
IEEE/The Open Group 2003 MKFIFO(P)
