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The Open method opens the associated object and prepares it for Read or Write operations. This operation is valid only if the storage object represents a file.
Syntax
HRESULT Open(UINTfuMode);
Parameters
fuMode
[in] Mode in which the file must be opened. It must be one of the following two values.
| Value | Description |
| MDSP_READ | Query whether a subsequent call to Read would be allowed. |
| MDSP_WRITE | Query whether a subsequent call to Insert would be allowed. |
Return Values
The method returns an HRESULT. All the interface methods in Windows Media Device Manager can return any of the following classes of error codes:
- Standard COM error codes
- Windows error codes converted to HRESULT values
- Windows Media Device Manager error codes
For an extenstive list of possible error codes, see Error Codes.
Possible values include, but are not limited to, those in the following table.
| Return code | Description |
| S_OK | The method succeeded. |
| WMDM_E_BUSY | The media device is busy. |
| ERROR_TOO_MANY_OPEN_FILES | Cannot open any more files. |
| WMDM_E_INTERFACEDEAD | The file or folder was previously deleted. |
| E_INVALIDARG | The fuMode parameter is an invalid or NULL pointer. |
| E_FAIL | An unspecified error occurred. |
Remarks
If the underlying file-system does not support opening of multiple files at the same time, the service provider should gracefully the return Win32 error code ERROR_TOO_MANY_OPEN_FILES, if the client attempts to open more than one file at a time.
This method must be implemented. It must not return WMDM_E_NOTSUPPORTED or E_NOTIMPL. For more information, see Mandatory and Optional Interfaces.
Requirements
Header: Defined in mswmdm.h.
Library: mssachlp.lib
See Also