SnmpFreeVbl function (winsnmp.h)

Article
10/13/2021

[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 SnmpFreeVbl function releases resources associated with a variable bindings list. These are resources allocated previously by a call to the SnmpCreateVbl function or the SnmpDuplicateVbl function in a WinSNMP application.

Syntax

SNMPAPI_STATUS SNMPAPI_CALL SnmpFreeVbl(
  [in] HSNMP_VBL vbl
);

Parameters

[in] vbl

Handle to the variable bindings list to release.

Return value

If the function succeeds, the return value is SNMPAPI_SUCCESS.

If the function fails, the return value is SNMPAPI_FAILURE. To get extended error information, call SnmpGetLastError specifying a NULL value in its session parameter. The SnmpGetLastError function can return one of the following errors.

Return code	Description
SNMPAPI_NOT_INITIALIZED	The SnmpStartup function did not complete successfully.
SNMPAPI_ALLOC_ERROR	An error occurred during memory allocation.
SNMPAPI_VBL_INVALID	The vbl parameter is invalid.
SNMPAPI_OTHER_ERROR	An unknown or undefined error occurred.

Remarks

The WinSNMP application must release the resources associated with each variable bindings list. It should do this by matching each call to the SnmpCreateVbl and SnmpDuplicateVbl functions with a corresponding call to the SnmpFreeVbl function. To avoid memory leaks, a WinSNMP application must call SnmpFreeVbl before it reuses the handle to a variable bindings list in a subsequent call to SnmpCreateVbl or SnmpDuplicateVbl.

If the application calls the SnmpClose or the SnmpCleanup function, the Microsoft WinSNMP implementation frees all resources it allocates for the WinSNMP session. However, even if the application does not reuse a variable bindings list handle, it is recommended that the application free individual variable bindings resources with the SnmpFreeVbl function. This reduces the implementation's work load, and should enhance its service to all applications. For additional information, see WinSNMP Data Management Concepts.

Requirements

Requirement	Value
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