[This is preliminary documentation and subject to change.]
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 manager application.
SNMPAPI_STATUS SnmpFreeVbl(
HSNMP_VBL vbl // handle to the variable bindings list
);
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. 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_VBL_INVALID | The vbl parameter is invalid. |
| SNMPAPI_OTHER_ERROR | An unknown or undefined error occurred. |
The WinSNMP manager 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 manager 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.
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.
WinSNMP Manager API Overview, WinSNMP Functions, SnmpDuplicateVbl, SnmpCreateVbl, SnmpClose, SnmpCleanup