Specifications

System Macros Invoked by Drivers
DDTAB
DDTAB
Generates a driver dispatch table (DDT) labeled devnam$DDT.
Format
DDTAB devnam ,[start=+IOC$RETURN] ,[unsolic=+IOC$RETURN] ,functb
[,cancel=+IOC$RETURN] [,regdmp=+IOC$RETURN] [,diagbf=0]
[,erlgbf=0] [,unitinit=+IOC$RETURN] [,altstart=+IOC$RETURN]
[,mntver=+IOC$MNTVER] [,cloneducb=+IOC$RETURN]
Parameters
devnam
Generic name of the device.
[start=+IOC$RETURN]
Address of start-I/O routine.
[unsolic=+IOC$RETURN]
Address of the routine that services unsolicited interrupts from the device. Only
MASSBUS device drivers use this field.
functb
Address of the driver’s function decision table.
[cancel=+IOC$RETURN]
Address of cancel-I/O routine.
[regdmp=+IOC$RETURN]
Address of the routine that dumps the device registers to an error message buffer
or to a diagnostic buffer.
[diagbf=0]
Length in bytes of the diagnostic buffer.
[erlgbf=0]
Length in bytes of the error message buffer.
[unitinit=+IOC$RETURN]
Address of unit initialization routine. MASSBUS drivers should use this field
rather than CRB$L_INTD+VEC$L_UNITINIT. UNIBUS, Q22–bus, and generic
VAXBI drivers can use either one.
[altstart=+IOC$RETURN]
Address of alternate start-I/O routine. To initiate this routine, a driver FDT
routine exits by means of system routine EXE$ALTQUEPKT instead of
EXE$QIODRVPKT.
[mntver=+IOC$MNTVER]
Address of the system routine that is called at the beginning and end of a mount
verification operation. The default, IOC$MNTVER, is suitable for all single-
stream disk drives. Use of this field to call any other routine is reserved to
Digital.
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