PROLOG

       This  manual  page  is part of the POSIX Programmer's Manual.  The Linux implementation of this interface
       may differ (consult 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 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(1POSIX)