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midiOutCachePatches
The midiOutCachePatches function requests that an internal MIDI synthesizer device preload and cache
a specified set of patches.
MMRESULT midiOutCachePatches(
HMIDIOUT hmo,
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| UINT wBank,
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| WORD * lpPatchArray,
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| UINT wFlags
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| );
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Parameters
hmo
Handle of the opened MIDI output device. This device must be an internal MIDI
synthesizer. This parameter can also be the handle of a MIDI stream, cast to HMIDIOUT.
wBank
Bank of patches that should be used. This parameter should be set to zero to
cache the default patch bank.
lpPatchArray
Address of a PATCHARRAY array indicating the patches to be cached or uncached.
wFlags
Options for the cache operation. It can be one of the following flags:
MIDI_CACHE_ALL
Caches all of the specified patches. If they cannot all be cached, it caches
none, clears the PATCHARRAY array, and returns MMSYSERR_NOMEM.
MIDI_CACHE_BESTFIT
Caches all of the specified patches. If they cannot all be cached, it caches
as many patches as possible, changes the PATCHARRAY array to reflect which
patches were cached, and returns MMSYSERR_NOMEM.
MIDI_CACHE_QUERY
Changes the PATCHARRAY array to indicate which patches are currently cached.
MIDI_UNCACHE
Uncaches the specified patches and clears the PATCHARRAY array.
Return Values
Returns MMSYSERR_NOERROR if successful or an error otherwise. Possible error
values include the following:
MMSYSERR_INVALFLAG
| The flag specified by wFlags is invalid.
| MMSYSERR_INVALHANDLE
| The specified device handle is invalid.
| MMSYSERR_INVALPARAM
| The array pointed to by lpPatchArray is invalid.
| MMSYSERR_NOMEM
| The device does not have enough memory to cache all of the requested patches.
| MMSYSERR_NOTSUPPORTED
| The specified device does not support patch caching.
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Remarks
Some synthesizers are not capable of keeping all patches loaded simultaneously
and must load data from disk when they receive MIDI program change messages.
Caching patches ensures that the specified patches are immediately available.
Each element of the PATCHARRAY array represents one of the 128 patches and has bits set for each of the 16
MIDI channels that use the particular patch. The least-significant bit
represents physical channel 0, and the most-significant bit represents physical channel
15 (0x0F). For example, if patch 0 is used by physical channels 0 and 8,
element 0 would be set to 0x0101.
This function applies only to internal MIDI synthesizer devices. Not all
internal synthesizers support patch caching. To see if a device supports patch
caching, use the MIDICAPS_CACHE flag to test the dwSupport member of the MIDIOUTCAPS structure filled by the midiOutGetDevCaps function.
See Also
PATCHARRAY, MIDIOUTCAPS, midiOutGetDevCaps
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