SnmpDecodeMsg

[This is preliminary documentation and subject to change.]

The WinSNMP SnmpDecodeMsg function decodes an encoded SNMP message into its components. This function performs the opposite action of the WinSNMP SnmpEncodeMsg function. 

SNMPAPI_STATUS SnmpDecodeMsg(
  HSNMP_SESSION session,     // handle to the WinSNMP session 
  LPHSNMP_ENTITY srcEntity,  // handle to the source entity 
  LPHSNMP_ENTITY dstEntity,  // handle to the target entity 
  LPHSNMP_CONTEXT context,   // handle to the context 
  LPHSNMP_PDU pdu,           // handle to the PDU 
  smiLPCOCTETS msgBufDesc    // pointer to the message buffer 
);

Parameters

session
Handle to the WinSNMP session. This parameter is required. For additional information, see the following Remarks section.
srcEntity
Pointer to a variable that receives a handle to the management entity.
dstEntity
Pointer to a variable that receives a handle to the target management entity.
context
Pointer to a variable that receives a handle to the context (a set of managed object resources) that the target management entity controls.
pdu
Pointer to a variable that receives a handle to the SNMP protocol data unit (PDU).
msgBufDesc
Pointer to an smiOCTETS structure that contains the SNMP message to decode into its components. The len member of the structure specifies the maximum number of bytes to process; the ptr member points to the encoded SNMP message.

Return Values

If the function succeeds, the return value is the number of decoded bytes. This value can be equal to, or less than, the len member of the smiOCTETS structure pointed to by the msgBufDesc parameter.

If the function fails, the return value is SNMPAPI_FAILURE. To get extended error information, call SnmpGetLastError. The SnmpGetLastError function can return one of the following errors.

Error code Description
SNMPAPI_NOT_INITIALIZED The SnmpStartup function did not complete successfully.
SNMPAPI_ALLOC_ERROR An error occurred during memory allocation.
SNMPAPI_SESSION_INVALID The session parameter is invalid.
SNMPAPI_ENTITY_INVALID One or both of the entity parameters is invalid.
SNMPAPI_CONTEXT_INVALID The context parameter is invalid.
SNMPAPI_PDU_INVALID The pdu parameter is invalid.
SNMPAPI_OUTPUT_TRUNCATED The output buffer length is insufficient. No output parameters were created.
SNMPAPI_MESSAGE_INVALID The SNMP message format in the buffer indicated by the msgBufDesc parameter is invalid. No output parameters were created.
SNMPAPI_OTHER_ERROR An unknown or undefined error occurred.

Remarks

The Microsoft WinSNMP implementation allocates resources to the WinSNMP manager application as a result of a successful call to the SnmpDecodeMsg function. It is recommended that the WinSNMP manager application free individual resources with the WinSNMP function that corresponds to the resource. For additional information, see Freeing WinSNMP Descriptors and WinSNMP Data Management Concepts.

QuickInfo

  Windows NT: Requires version 5.0 or later. Available as a redistributable for Windows NT 4.0.
  Windows: Unsupported.
  Windows CE: Unsupported.
  Header: Declared in winsnmp.h.
  Import Library: Use wsnmp32.lib.

See Also

WinSNMP Manager API Overview, WinSNMP Functions, SnmpEncodeMsg, SnmpFreeEntity, SnmpFreeContext, SnmpFreePdu, SnmpSendMsg, smiOCTETS