IMiniportMidiStream::Read method (portcls.h)
The Read method reads data from an incoming MIDI stream.
Syntax
NTSTATUS Read(
[in] PVOID BufferAddress,
[in] ULONG BufferLength,
[out] PULONG BytesRead
);
Parameters
[in] BufferAddress
Specifies the address of a caller-allocated buffer. The method copies the incoming MIDI data from the device to the buffer. The allocated size of this buffer must be greater than or equal to BufferLength.
[in] BufferLength
Specifies the length in bytes of the buffer pointed to by BufferAddress.
[out] BytesRead
Output pointer to a caller-allocated variable into which the method writes a count specifying the actual number of bytes successfully read from the device into the buffer.
Return value
Read returns STATUS_SUCCESS if the call was successful. Otherwise, the method returns an appropriate error code. The following table shows some of the possible return status codes.
| Return code | Description |
|---|---|
|
Invalid device request (for example, calling Read on a MIDI output stream).
|
Remarks
The miniport driver calls IPortMidi::Notify to notify the port driver when incoming MIDI data becomes available from the capture device. The port driver calls IMiniportMidi::Read to retrieve the data. The port driver continues to call Read as long as more data is available.
The Read method returns STATUS_SUCCESS and a BytesRead count of zero to indicate that no more MIDI input data is currently available from the device.
Requirements
| Requirement | Value |
|---|---|
| Target Platform | Universal |
| Header | portcls.h (include Portcls.h) |
| IRQL | DISPATCH_LEVEL |