IUPnPService::QueryStateVariable
A version of this page is also available for
4/8/2010
This method returns the value of one of the service's state variables.
Syntax
HRESULT QueryStateVariable(
BSTR bstrVariableName,
VARIANT* pvarValue
);
Parameters
- bstrVariableName
[in] Specifies the state variable for which to return a value. All variable names are case sensitive.
- pvarValue
[out] Receives a reference to the value of the variable specified by bstrVariableName. The type of the data returned depends on the state variable for which the query was invoked.
Return Value
- S_OK
This method was successful.
Otherwise, the method returns either one of the COM error codes defined in WinError.h, or one of the following UPnP-specific return values.
| UPnP-specific return value | Description |
|---|---|
UPNP_E_DEVICE_ERROR |
Variable is not evented and the remote query returned an error code. This is not a transport error; the device received the request, but it returned an error. |
UPNP_E_DEVICE_TIMEOUT |
The device has not responded within the 30–second time-out period. |
UPNP_E_INVALID_VARIABLE |
Variable does not exist. |
UPNP_E_PROTOCOL_ERROR |
Query was not completed because of problems at the UPnP protocol level. |
UPNP_E_TRANSPORT_ERROR |
Variable is not evented and the remote query for the value failed because of an HTTP problem. Use IUPnPService::LastTransportStatus to retrieve the HTTP error code. |
Remarks
The UPnP Forum discourages use of this method. If possible, use a service-specific action, if one has been provided.
Requirements
| Header | upnp.h |
| Library | uuid.lib |
| Windows Embedded CE | Windows CE .NET 4.0 and later |
| Windows Mobile | Windows Mobile Version 5.0 and later |