Specifications

System Macros Invoked by Drivers
CLASS_UNIT_INIT
CLASS_UNIT_INIT
Generates the common code that must be executed by the unit initialization
routine of all terminal port drivers.
Format
CLASS_UNIT_INIT
Description
A terminal port driver’s unit initialization routine invokes the CLASS_UNIT_
INIT macro to perform initialization tasks common to all port drivers. To use
the CLASS_UNIT_INIT macro, the driver must include an invocation of the
$TTYMACS definition macro (from SYS$LIBRARY:LIB.MLB).
The CLASS_UNIT_INIT macro binds the terminal port and class driver into a
single, complete driver by initializing the following UCB fields as indicated:
Field Contents
UCB$L_TT_CLASS Class driver vector table address
UCB$L_TT_PORT Port driver vector table address
UCB$L_TT_GETNXT Address of the class driver’s get-next-character
routine (CLASS_GETNXT)
UCB$L_TT_PUTNXT Address of the class driver’s put-next-character
routine (CLASS_PUTNXT)
UCB$L_DDT Address of the terminal class driver’s driver
dispatch table
Before invoking this macro, the unit initialization should place in R0 the address
of the port driver vector table.
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