Envoy Application Programming Manual

Burroughs Point-To-Point Protocol
Envoy Application Programming Manual—427159-001
9-10
READ Procedure
Table 9-9 shows the file-system errors that may occur on an initial READ.
Continuation READ (Line in READ State)
All READs following the initial one are continuation READs. A continuation READ
(Example 9-2) causes Envoy, on behalf of the application process, to send the proper
acknowledgment for the preceding message, read the next message, and return the
message to the buffer of the application process. The successful receipt of a message is
indicated by a condition code of CCE upon completion of the READ. Following receipt
of an initial message, the line is in the READ state.
Table 9-9. Initial READ File-System Errors
Error Numbers Description
Resultant Line State
0 No error. A station responded with a mes-
sage. Message is returned to the buffer of the
application process.
READ
160 Request is invalid for device state; protocol
error.
CONTROL
161 Impossible event occurred for line state. CONTROL
171 No bid received. No line bid was received
within the timeout and retry limits.
CONTROL
172 Reply not proper for protocol. The data
received while waiting for a line bid or for a
message was not proper for the protocol.
CONTROL
173 Transmission error. Text was received with a
character parity error or a block-check char-
acter error. A NAK was sent, and the mes-
sage was retransmitted the number of times
specified by the retry value.
CONTROL
177 Text overrun. Either the data received while
waiting for a line bid exceeds three charac-
ters or the message received exceeds the
length specified in the read count parameter.
The READ was attempted the number of
times specified by the retry value.
CONTROL
Example 9-2. Continuation READ
Local Remote
line state = READ
CALL READ(...)
| ACK -->
| <-- message
(READ completes)
error = 0
line state = READ