INT 2Fh (47)             Multiplex Interrupt (PRINT)                . DOS 3.1

    Provides control of the PRINT spooler.

       On entry:      AH         01h
                      AL         Function to be performed

       Functions:     AL         0        Get installed state
                                 1        Submit file
                                 2        Cancel file
                                 3        Cancel all files
                                 4        Status
                                 5        End of status

       Error codes:   1          Invalid function
                      2          File not found
                      3          Path not found
                      4          Too many open files
                      5          Access denied
                      8          Queue full
                      9          Busy
                      12         Name too long
                      15         Invalid drive

       Returns:       See below

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    AL = 0      Get Installed State

       On entry:      AH         01h
                      AL         00h

       Returns:       AL         00h     Not installed, okay to install
                                 01h     Not installed, not okay to install
                                 FFh     Installed

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    AL = 1      Submit File

       On entry:      AH         01h
                      AL         01h
                      DS:DX      Pointer to submit packet

       Returns:       AX         Error code (see above)

    The submit packet must include a "level" value (one byte; for DOS 3.1
    through 3.3, the level value must be 0), followed by an ASCIIZ string
    containing the drive, path, and filename of the file to be printed.
    Wildcard characters are not supported.

  --------------------------------------------------------------------------

    AL = 2      Cancel File (remove from queue)

       On entry:      AH         01h
                      AL         02h
                      DS:DX      Pointer to ASCIIZ string specifying file to
                                 be cancelled.

       Returns:       AX         Error code (see above)

    Wildcard characters are supported.

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    AL = 3      Cancel All Files (purge queue)

       On entry:      AH         01h
                      AL         03h

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    AL = 4      Status (inspect queue)

       On entry:      AH         01h
                      AL         04h

       Returns:       DX         Error count
                      DS:SI      Pointer to print queue

    The error count reports the number of consecutive failures experienced
    by PRINT in outputting the most recent character.

    The print queue, pointed to by DS:SI, is a series of 64-byte entries
    specifying the files to be printed. The file currently being printed
    appears first. The end of the queue is indicated by an entry beginning
    with 00h.

    A call to Status freezes the files in the queue. Call End of Status
    (AL=5) to release the files for printing.

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    AL = 5      End of Status

       On entry:      AH         01h
                      AL         05h

       Returns:       AX         Error code (see above)