SnmpGetLastError function (winsnmp.h)

[SNMP is available for use in the operating systems specified in the Requirements section. It may be altered or unavailable in subsequent versions. Instead, use Windows Remote Management, which is the Microsoft implementation of WS-Man.]

The WinSNMP SnmpGetLastError function returns the calling application's last-error code value. The value indicates the reason why the last function call executed by the WinSNMP application failed.


  [in] HSNMP_SESSION session


[in] session

Handle to the WinSNMP session. This parameter can also be NULL.

In certain cases, when a function call fails you can pass a NULLsession value to the SnmpGetLastError function to retrieve the last-error code value. This is true for function calls that do not involve a session parameter, and cases in which the session parameter value is invalid. These cases are noted in the Return Values section on the function's reference page.

A single-thread application can pass a NULLsession value to SnmpGetLastError to retrieve last-error information for the entire application.

For more information, see the following Remarks and Return Values sections.

Return value

If the session parameter is a valid WinSNMP session handle, the SnmpGetLastError function returns the last WinSNMP error that occurred for the indicated session.

If the session parameter is NULL — for example, if the SnmpStartup function fails, SnmpGetLastError returns the last WinSNMP error that occurred.


A WinSNMP application must call SnmpGetLastError immediately after a function fails, to retrieve the last-error code. If another function fails, it overwrites the last-error code set by the most recently failed function. For more information, see WinSNMP Error Codes.

Although the session parameter accommodates both multithread and single-thread Windows operating environments, the potential still exists for the last-error code from one thread to overwrite the last-error code from another thread.

Note that SnmpGetLastError must be able to return the last-error code to a WinSNMP application under the following conditions:

  • After the SnmpStartup function fails
  • Before the SnmpCreateSession function creates any WinSNMP sessions for the instance of the application
  • After the SnmpClose function closes all WinSNMP sessions for the instance of the application
  • After the SnmpCleanup function disconnects the WinSNMP application from the Microsoft WinSNMP implementation


Minimum supported client Windows 2000 Professional [desktop apps only]
Minimum supported server Windows 2000 Server [desktop apps only]
Target Platform Windows
Header winsnmp.h
Library Wsnmp32.lib
DLL Wsnmp32.dll

See also





WinSNMP Functions

WinSNMP API Overview