message

    OpenVMS usage:char_string
    type:         character string
    access:       read only
    mechanism:    by descriptor
    Message items that SMB$READ_MESSAGE_ITEM is to read. The message
    argument is the address of a descriptor of a buffer. The buffer
    is the one that contains the message items that SMB$READ_MESSAGE_
    ITEM is to read. The buffer specified here must be the same as
    that specified with the call to the SMB$READ_MESSAGE routine,
    which fills the buffer with the contents of the message.

 context

    OpenVMS usage:context
    type:         longword (unsigned)
    access:       modify
    mechanism:    by reference
    Value initialized to 0 specifying the first message item in
    the buffer to be read. The context argument is the address of a
    longword that the SMB$READ_MESSAGE_ITEM routine uses to determine
    the next message item to be returned. When this value is 0,
    it indicates that SMB$READ_MESSAGE_ITEM is to return the first
    message item.

    The SMB$READ_MESSAGE_ITEM routine updates this value each time it
    reads a message item. SMB$READ_MESSAGE_ITEM sets the value to 0
    when it has returned all the message items in the buffer.

 item_code

    OpenVMS usage:smb_item
    type:         longword (unsigned)
    access:       write only
    mechanism:    by reference
    Item code specified in the message item that identifies its type.
    The item_code argument is the address of a longword into which
    SMB$READ_MESSAGE_ITEM writes the code that identifies which item
    it is returning.

    The codes that identify message items are defined at the end of
    the Description help topic for this routine.

 buffer

    OpenVMS usage:char_string
    type:         character string
    access:       write only
    mechanism:    by descriptor
    Message item. The buffer argument is the address of a descriptor
    of a buffer. The buffer is the one in which the SMB$READ_MESSAGE_
    ITEM routine is to place the message item data. SMB$READ_MESSAGE_
    ITEM uses the Run-Time Library string-handling (STR$) routines to
    copy the message item data into the buffer.

 size

    OpenVMS usage:word_unsigned
    type:         word (unsigned)
    access:       write only
    mechanism:    by reference
    Size of the message item. The size argument is the address of a
    word in which the SMB$READ_MESSAGE_ITEM is to place the size, in
    bytes, of the item's data.