Function 5Ah            Create Temporary File                        DOS 3.0+

    Creates a file with a unique name and returns both a handle for
    the file and the new filename.

        Entry   AH    = 5Ah
                CX    = File attributes
                DS:DX = Pointer to path ending in \ (ASCIIZ string)

        Return  AX = File handle
                Unique filename appended to path (ASCIIZ string)
                or
                AX = Error code, if CF is set
                     | 03h Path not found
                     | 04h No handle available
                     | 05h Access denied

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    Before function 5ah is invoked, DS:DX must point to a string that
    specifies the path for the temporary file; the path must end with
    a backslash (\) and a zero. The program must reserve the 13 bytes
    immediately following the terminating zero to hold the temporary
    filename.
    The file attributes parameter can be a combination of:
    attr_normal, attr_readonly, attr_hidden, attr_system, attr_archive.


    When DOS creates a file, it opens it with read-and-write access
    and compatibility sharing mode and sets the file pointer to zero.
    If the attr_readonly attribute is specified, it takes affect only
    after the new file is closed.

    DOS does not delete temporary files; programs using temporary
    files should delete them when they are no longer in use.