IWMDMOperation::BeginRead method (mswmdm.h)
The BeginRead method indicates that a "read from device" action is beginning. Windows Media Device Manager only calls this method if the application calls IWMDMStorageControl::Read and passes in this IWMDMOperation interface.
Syntax
HRESULT BeginRead();
Return value
The application should return one of the following HRESULT values.
| Return code | Description |
|---|---|
|
The read operation should continue. |
|
The read operation should be cancelled without finishing. |
|
An unspecified error occurred, and the read operation should be cancelled without finishing. |
Remarks
This method is called just before the Windows Media Device Manager calls IWMDMOperation::TransferObjectData.
Examples
The following C++ code example implements the BeginRead method and outputs a message when a read-from-device action is beginning.
HRESULT BeginRead()
{
// TODO: Display the message: "IWMDMOperation event--BeginRead."
// If the global handle of the source file is uninitialized, fail.
if (m_File == INVALID_HANDLE_VALUE)
return E_FAIL;
// Global status to let TransferObjectData know what kind of
// operation is happening.
m_OperationStatus = OPERATION_READ;
return S_OK;
}
Requirements
| Requirement | Value |
|---|---|
| Target Platform | Windows |
| Header | mswmdm.h |
| Library | Mssachlp.lib |