INT E0 - ConcCP/M,DR Multiuser DOS - "Q_OPEN" - OPEN MESSAGE QUEUE
        CL = 87h
        DS:DX -> queue parameter block (see below)
Return: AX = status
            0000h success
            FFFFh failure
        CX = error code
SeeAlso: INT E0/CL=86h,INT E0/CL=89h

Format of queue parameter block:
Offset  Size    Description
 00h    WORD    internal use, initialize to zero
 02h    WORD    queue ID (set by INT E0/CL=87h)
 04h    WORD    internal use, initialize to zero
 06h    WORD    offset of queue message buffer
 08h  8 BYTEs   queue name

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