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
File-System Procedures
Envoy Application Programming Manual—427159-001
C-7
CANCEL
CANCEL
The CANCEL procedure is used to cancel the oldest incomplete operation on a nowait
file. This procedure can only be used on a full-duplex line.
The form of the CANCEL procedure is:
filenum input
INT:value
is the number of an open file whose oldest incomplete operation you want to cancel.
Condition Codes
Example
CALL CANCEL ( some^file );
IF < THEN ... ! no operation outstanding.
CHANGELIST
This procedure is used only when the application program is acting as a supervisor or
tributary station in a centralized multipoint configuration.
For a supervisor station, a call to the CHANGELIST procedure performs one of the
following three operations:
•
Enables or disables polling or selection of a particular station
•
Specifies continuous or noncontinuous polling
•
Resumes polling of partially disabled (that is, nonresponding) stations
Note that if a READ is outstanding when the call to CHANGELIST is made (that is,
polling is in progress), the specified changes do not take effect until the current READ
completes either on its own or as the result of a call to HALTPOLL.
CALL CANCEL ( filenum); !i
< (CCL) Indicates that an error occurred (call FILEINFO).
= (CCE) Indicates that the CANCEL procedure completed successfully. (This does
not necessarily indicate that data attributed to a cancelled WRITE request
was not transmitted. The CANCEL procedure simply terminates a
WRITE request and any further transmission of data, but does not cancel
any data that has been transmitted prior to the completion of the
CANCEL procedure.)
> (CCG) Is not returned by CANCEL.