IWMDMOperation::BeginRead method (mswmdm.h)

Article
02/22/2024

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
S_OK	The read operation should continue.
WMDM_E_USER_CANCELLED	The read operation should be cancelled without finishing.
E_FAIL	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