SNAX/HLS Application Programming Manual

Executing a Verb Request
Application Prototyping and Simulation (APS) System
104707 Tandem Computers Incorporated 6–7
The SNAX/HLS server executes the verb request and returns the reply. APS formats
the reply and displays it in the lower part of the screen.
Visual Indication of Progress
APS uses reverse video to help you know what’s happening. The function-key label
for the verb on display is shown in reverse video until you press the SEND key
(function key F12). When you press SEND, the verb label returns to normal display
while the SEND label appears in reverse video. When the reply arrives, the SEND
label returns to normal display and the verb label appears again in reverse video.
Error Information in Replies When errors occur in verb execution, APS displays several information fields,
including the name of the reply, return code, system error, user error, and retry action,
described below. Figure 6-3 shows these fields for an OPEN-SESSION request that
completed with a syntax error.
Return Code
Displays the decimal value (5) of the RETURN-CODE field of the verb reply
together with a standard return-code label obtained by a
CONVERT-ERROR-CODE request. See Section 4, “The Standard Verb Interface,”
for more information on return codes and Section 5, “SNAX/HLS Verbs,” for
more information on the CONVERT-ERROR-CODE verb.
System Error
Contains the following fields:
The decimal value of SYSTEM-ERROR-CODE (that is, 1).
The hexadecimal value of SYSTEM-ERROR-CODE (that is, %H0001). This
value is useful in decoding SNA negative responses.
A textual equivalent for SYSTEM-ERROR-CODE (where relevant) as obtained
by a CONVERT-ERROR-CODE request. If this field contains an SNA defined
error (for example, %H0801), an explanatory message is displayed. If, as in
the case shown in Figure 6-3, the system error is not defined in SNA, a suitable
message is displayed.
A special convention applies for the case of RC-SYNTAX-ERRORS: SYSTEM-
ERROR-CODE points to the parameter in error (excluding the server name,
session ID, and the completion code). In Figure 6-3, SYSTEM-ERROR-CODE
points to parameter one of the verb request (the LU name). In this case, the
LU name (#snap) must be moved leftward by one position to be above the
circumflex (^). Uppercase or lowercase letters are, however, equally
acceptable.
User Error
Displays the decimal and hexadecimal value of USER-ERROR-CODE of the verb
reply.