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  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 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, 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)