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



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

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:

        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 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 IEEE Std 1003.1-2001, Section 8.2, Internationalization Variables for the precedence  of  international-
              ization 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 stan-
              dard 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  Inter-
       faces  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 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 Operating System Interface (POSIX), The Open Group Base Specifications Issue 6,  Copy-
       right (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.open-
       group.org/unix/online.html .



IEEE/The Open Group                                           2003                                                    MKFIFO(1P)