IMFAttributes::GetAllocatedString Method
Gets a wide-character string associated with a key. This method allocates the memory for the string.
Syntax
HRESULT GetAllocatedString(
[in] REFGUID guidKey,
[out] LPWSTR *ppwszValue,
[out] UINT32 *pcchLength
);
Parameter
guidKey [in]
A GUID that identifies which value to retrieve. The attribute type must be MF_ATTRIBUTE_STRING.ppwszValue [out]
If the key is found and the value is a string type, this parameter receives a copy of the string. The caller must free the memory for the string by calling CoTaskMemFree.pcchLength [out]
Receives the number of characters in the string, excluding the terminating NULL character. This parameter must not be NULL.
Rückgabewert
The method returns an HRESULT. Possible values include, but are not limited to, those in the following table.
| Rückgabecode | Beschreibung |
|---|---|
| S_OK | The method succeeded. |
| MF_E_ATTRIBUTENOTFOUND | The specified key was not found. |
| MF_E_INVALIDTYPE | The attribute value is not a string. |
Hinweise
To copy a string value into a caller-allocated buffer, use the IMFAttributes::GetString method.
This interface is available on the following platforms if the Windows Media Format 11 SDK redistributable components are installed:
- Windows XP mit Service Pack 2 (SP2) und höher.
- Windows XP Media Center Edition 2005 with KB900325 (Windows XP Media Center Edition 2005) and KB925766 (Oktober 2006 Updaterollup für Windows XP Media Center Edition) installed.
Hinweis An earlier version of the documentation incorrectly stated that the pcchLength parameter can be NULL. Setting this parameter to NULL might succeed in some cases, but is not guaranteed. The caller must pass a non-NULL pointer for this parameter.
Anforderungen
Mindestens unterstützter Client |
Windows Vista |
Mindestens unterstützter Server |
Windows Server 2008 |
Header |
Mfobjects.h (include Mfidl.h) |
Bibliothek |
Mfuuid.lib |