Compaq AAR04BCTE manual eSNMP API Routines set Routine

eSNMP API Routines

*_set Routine

If any row reports failure, all rows that were successfully committed are told to undo the phase. This is accomplished by calling a single method routine for each row (the same one that was called for the commit phase), with a method->actionequal to ESNMP_ACT_UNDO.

4.Each row is released. The same single method routine for each row is called with a method->actionequal to ESNMP_ACT_CLEANUP. This occurs for every row, regardless of the results of previous processing.

The action codes are processed as follows:

•ESNMP_ACT_SET

Each object’s method routine is called during the SET phase, until all objects are processed or a method routine returns an error status value. (This is the only phase during which each object’s method routine is called.) For variable bindings in the same conceptual row, method->rowpoints to a common ROW_

CONTEXT.

The method->flagsbitmask has the ESNMP_LAST_IN_ROW bit set, if this is the last object being called for this ROW_CONTEXT. This enables you to do a final consistency check, because you have seen every variable binding for this conceptual row.

The method routine’s job in this phase is to determine whether the Set request will work, to return the correct SNMP error code if it does not, and to prepare any context data it needs to actually perform the Set request during the COMMIT phase.

The method->row->contextfield is private to the method routine; libesnmp does not use it. A typical use is to store the address of an emitted structure that has been loaded with the data from the VARBIND for the conceptual row.

•ESNMP_ACT_COMMIT

Even though several variable bindings may be in a conceptual row, only the last one in order of the Set request is processed. Of all the method routines that point to a common row, only the last method routine is called.

This method routine must have available to it all necessary data and context to perform the operation. It must also save a snapshot of current data or whatever it needs to undo the Set operation, if required. The method->row->savefield is intended to hold a pointer to whatever data is needed to accomplish this. A typical use is to store the address of a structure that has been loaded with the current data for the conceptual row. The structure is one that has been automatically generated by the MIBCOMP command.

The method->row->savefield is also private to the method routine; libesnmp does not use it.

If this operation succeeds, return ESNMP_MTHD_noError; otherwise, return a value of ESNMP_MTHD_commitFailed.

If any errors were returned during the COMMIT phase, libesnmp enters the UNDO phase; if not, it enters the CLEANUP phase.

Note

If the Set request spans multiple subagents and another subagent fails, the UNDO phase may occur even if the Set operation is successful

eSNMP API Routines 5–25