Information
The topic you requested is included in another documentation set. For convenience, it's displayed below. Choose Switch to see the topic in its original location.

Allocating and Preparing MIDI Data Blocks

The midiOutLongMsg, midiInAddBuffer, and midiStreamOut functions require that applications to allocate data blocks to pass to the device drivers for playback or recording purposes. Each of these functions uses a MIDIHDR structure to describe its data block.

Before you use one of these functions to pass a data block to a device driver, you must allocate memory for the buffer and the header structure that describes the data block.

Windows provides the following functions for preparing and cleaning up MIDI data blocks.

Value Meaning
midiInPrepareHeader Prepares a MIDI input data block.
midiInUnprepareHeader Cleans up the preparation of a MIDI input data block.
midiOutPrepareHeader Prepares a MIDI output data block.
midiOutUnprepareHeader Cleans up the preparation of a MIDI output data block.

 

Before you pass a MIDI data block to a device driver, you must prepare the buffer by passing it to the midiInPrepareHeader or midiOutPrepareHeader function. When the device driver is finished with the buffer and returns it, you must clean up this preparation by passing the buffer to the midiInUnprepareHeader or midiOutUnprepareHeader function before any allocated memory can be freed.

Related topics

MIDI Services

 

 

Show: