snmpAddVarBind result

SNMP_MGR_RC_OK if successful
SNMP_MGR_RC_NULL_PTR if either the varbinds parameter or the oid parameter is NULL
SNMP_MGR_RC_OUT_OF_MEMORY if sufficient storage could not be allocated for the new VarBind, the OID container, or the value container
SNMP_MGR_RC_INVALID_OID if an OID container cannot be created using this function's oid parameter
SNMP_MGR_RC_INVALID_VALUE if a value container cannot be created using this function's value parameter

Rule: You must call the snmpCreateVarBinds() function before you call this function, because the varbinds parameter that is used on this function is returned from the snmpCreateVarBinds() function.