Envoy Application Programming Manual
Table Of Contents
- What’s New in This Manual
- About This Manual
- 1 Application Programming With Envoy
- 7 ADM-2 Multipoint Supervisor Protocol
- 8 TINET Multipoint Supervisor Protocol
- 9 Burroughs Point-To-Point Protocol
- 10 Asynchronous Line Supervisor Protocol
- A ASCII Character Set
- B ASCII to EBCDIC Code Conversion
- C File-System Procedures
- D Statistics Messages
- E S-Series Changes to Envoy
- NonStop™ Himalaya S-Series Server Architecture
- G-Series Migration Considerations
- CBSENSEON and CFSENSEON Modifiers
- LEOTRESYN and NOLEOTRESYN Modifiers
- Treatment of Characters After the Termination Character
- Number of SYN Characters
- DTR Drop
- Reporting of Parity Error
- Half-Duplex Support for Asynchronous Lines
- Controller Replacement
- SYSGEN and COUP
- Unit Numbers
- FDX Line Changes
- No Support for Auto-Call Unit
- Glossary
- Index
BISYNC Centralized Multipoint Supervisor Protocol
Envoy Application Programming Manual—427159-001
4-15
Polling Type
The READ completes either when a station responds to a poll with a message or when a
line error is detected. If a station responds with a message, the entry number of the
station in the poll list is returned in linebuf.8:15 (see Message Formats
on page 4-22).
The message is also returned in the line buffer and a condition code of CCE is returned.
The line is in the READ state. If a line error is detected, the entry number associated
with the last station polled is returned in linebuf.8:15 and the READ completes with a
CCL indication.
Noncontinuous Polling
Noncontinuous polling occurs for a specified number of passes through the poll list or
until a tributary station responds to the poll with text or until an error occurs.
Noncontinuous polling operates in the same manner as continuous polling except that
the number of passes through the poll list is limited. The limit is specified through the
polling type parameter of the DEFINELIST procedure or the function parameter of the
CHANGELIST procedure.
If no tributary station responds with a message within the specified number of passes
through the poll list, polling stops and the READ completes with an error 176 (poll
sequence ended with no responder). The line is in the CONTROL state. Figure 4-4
shows the noncontinuous poll sequence.
Example 4-3. Continuous Polling
poll^type := 0;
CALL DEFINELIST (linefnum,addr^list,addr^size,num^entries,
poll^count,poll^type);
IF < THEN ...
CALL READ (linefnum, linebuf,..);
IF < THEN ...