ACC HDLC-NRM (SDLC) User's Guide

Using HDLC-NRM (SDLC) Protocols
Status and Error Messages
Chapter 3 37
Status and Error Messages
Error and other conditions are reported to the application program
through two kinds of status codes.
The defines for these status codes are located in zcomstatus.h and
zx25status.h.
Buffer Completion Statuses
Buffer completion statuses are generated by the protocol on all transmit
messages. Depending on the mode parameter selected when using the
zsend call, the application will see either no transmit response messages,
error responses only, or all transmit response messages. The status code
in these messages indicate either the successful transmission of the
message, or the reason why it could not be transmitted.
The buffer completion statuses listed in the following table may be
generated by the HDLC-NRM (SDLC) protocol.
Table 3-1 Buffer Completion Status
Status Code
Value
Description
IO_OK
(0)
No error detected.
This message was successfully transmitted to
and acknowledged (if appropriate) by the
receiving station.
IO_DSBL
(1)
Terminal disabled.
Messages cannot be transmitted to a disabled
terminal.
IO_TX_TMOUT
(2)
Cable or local modem fault.
This message cannot be sent or acknowledged
because a “transmit blockage” condition exists.