Envoy Application Programming Manual

TINET Multipoint Supervisor Protocol
Envoy Application Programming Manual—427159-001
8-16
Poll State
Poll State
Associated with each address in the poll list is a poll state bit. (The poll state bit is in the
most-significant bit position of the first element of each entry in the poll list). The
meanings of the states of the poll-state bit are:
0 = enable polling (the associated station is polled when a poll sequence is initiated)
1 = disable polling (the associated station is not polled)
By means of the poll-state bit, an application process can selectively designate whether
terminals in the poll list are to be polled.
The poll state for terminals is specified in either of two ways:
•
The poll states for all terminals are indicated by their poll-state bits in the address
list before the DEFINELIST procedure is called, or
•
The CHANGELIST procedure is called to alter a specific terminal’s poll state after
the DEFINELIST procedure has been called
Selective Polling (Before Calling DEFINELIST)
Example 8-6 shows how to disable polling for a specific terminal by means of the poll
state bit in the address list:
Example 8-6. Selective Polling (Before Calling DEFINELIST)
LITERAL addr^size = 3, ! address size in words.
num^entries = 6, ! number of address-list
! entries.
NUL = 0, ! ASCII NULL character.
EOT = 4, ! ASCII EOT character.
ENQ = 5, ! ASCII ENQ character.
poll^count = 3, ! number of poll-list entries.
no^poll = %200; ! used to set poll-state bit.
STRING
.saddr^list[ 0 : addr^size * num^entries * 2 - 1] :=
! address list.
[ EOT, EOT, %040, ENQ, ! terminal 1 poll.
no^poll + EOT, EOT, %041, ENQ, ! terminal 2 poll.
EOT, EOT, %042, ENQ, ! terminal 3 poll.
EOT, %060, NUL, NUL, ! terminal 1 select.
EOT, %061, NUL, NUL, ! terminal 2 select.
EOT, %062, NUL, NUL ] ; ! terminal 3 select.
INT .addr^list := @saddr^list ’>>’ 1; ! redefine as INT
! array.
CALL DEFINELIST (linefnum,addr^list,addr^size,num^entries,
poll^count,poll^type);
IF < THEN ...