[Info-vax] Mailbox driver analysis regarding greater than 65535 messages in mailbox

[Andy Burns]

Robert A. Brooks wrote:

> While it *might* be possible to promote UCB$W_MSGCNT to a longword (but 
> only for V9), that would not
> be good enough to solve the complete problem because . . .
> 
> In the I/O User's Guide, chapter 4 (the mailbox driver chapter),
> 
> "DVI$_DEVDEPEND returns a longword field in which the two low-order 
> bytes contain the number of messages in the mailbox.
> (The two high-order bytes are not used and should be ignored.)

If count exceeds MAXUINT16, return MAXUINT16 rather than the actual count?