SNAX/APN Application Programming Manual

Handling Errors in SNAX/APN Applications
SNAX/APN Application Programming Manual—420111-001
B-9
RU Sense Codes
RU Sense Codes
As an RU travels through the network to its intended destination, there are many points
at which an error could occur and a negative response be generated.
The user’s PLU or SLU process accepts incoming responses by means of read requests
(WRITEREAD with a nonzero read-count). Whenever a read request completes, the
user’s PLU or SLU process examines the SNAX/APN header in the associated buffer to
find out the nature of what has been received.
If the incoming RU is a negative response (RRI=1, RTI=1) and contains sense data
(SDI=1), then the PLU or SLU process extracts an RU sense code from the first four
bytes following the SNAX/APN header. The sense data provides some explanation as to
why the response is negative.
The first byte of an RU sense code identifies the general category of error, as shown in
Table B-6.
The second byte qualifies the error more specifically. For example, the sense data
X'0801' indicates a request reject because the required resource (LU, PU, or link
specified in the RU) was not available.
The third and fourth bytes can either further qualify the error condition or be used for
user-defined error conditions. For example, with the sense code X'0833' (INVALID
PARAMETER), the third and fourth bytes are used for identifying which parameter was
in error.
Table B-6. RU Sense Codes Error Categories
Value Category
X'80' Path error
X'40' RH usage error
X'20' State error
X'10' Request error
X'08' Request reject