MKFIFO(1)                  POSIX Programmer's Manual                 MKFIFO(1)



PROLOG
       This manual page is part of the POSIX Programmer's Manual.  The OS
       implementation of this interface may differ (consult the corresponding
       OS manual page for details of OS behavior), or the interface may not be
       implemented on OS.

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 POSIX.1-2017, 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
       POSIX.1-2017, 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 symbolic__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 POSIX.1-2017, 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 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
       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 System Interfaces volume of
       POSIX.1-2017. 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
       creation.

FUTURE DIRECTIONS
       None.

SEE ALSO
       chmod, umask

       The Base Definitions volume of POSIX.1-2017, Chapter _8, Environment
       Variables, Section 12.2, Utility Syntax Guidelines

       The System Interfaces volume of POSIX.1-2017, mkfifo()

COPYRIGHT
       Portions of this text are reprinted and reproduced in electronic form
       from IEEE Std 1003.1-2017, Standard for Information Technology --
       Portable Operating System Interface (POSIX), The Open Group Base
       Specifications Issue 7, 2018 Edition, Copyright (C) 2018 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 .

       Any typographical or formatting errors that appear in this page are
       most likely to have been introduced during the conversion of the source
       files to man page format. To report such errors, see
       https://www.kernel.org/doc/man-pages/reporting_bugs.html .



IEEE/The Open Group                  2017                            MKFIFO(1)
