usine chunks

UsineChunks

#example #chunks #persistence #advanced

Chunk-based shared data persistence between modules.

Module Name	usine chunks
Type	mtSimple
Color	clChunkModuleColor
Source	examples/UsineChunks/

Description

Demonstrates the Usine Chunks system for sharing named data between modules. Chunks are persistent key-value stores that survive save/load cycles and can notify subscribers when data changes.

Parameters

#	Name	Type	I/O	Callback
0	set item1	ptArray	Input	ctImmediate
1	commatxt idx 1	ptText	Input	ctImmediate
2	get item1	ptArray	Output	None
3	get commatxt	ptText	Output (DontSave)	None

How It Works

1. onInitModule: Gets/creates chunk "mychunk" via sdkGetChunk. Subscribes to notifications for chunk deletion, "item1" changes, and "commatxt" changes.
2. Writing: On input change, writes data to chunk items using sdkChunkOperation(..., coAddOrModifyItem)
3. Reading: On subscription notification, reads data from chunk using sdkChunkOperation(..., coGetItem)
4. Cleanup: Destructor calls sdkChunkUnSubscribeAll()

Chunk API Pattern

// Get or create a chunk
TUsineChunkPtr chunk = sdkGetChunk("mychunk");

// Write float array to chunk item
sdkChunkOperation(chunk, "item1", ftDataFloat,
    inputEvent, coAddOrModifyItem, 0);

// Write text to chunk item at index
sdkChunkOperation(chunk, "commatxt", ftTextGeneral,
    textEvent, coAddOrModifyItem, 1);

// Subscribe to changes (fires callbackID when item changes)
sdkChunkSubscribe(chunk, "item1", MY_CALLBACK_ID, TRUE);

// Read chunk item
sdkChunkOperation(chunk, "item1", ftDataFloat,
    outputEvent, coGetItem, 0);

// Cleanup
sdkChunkUnSubscribeAll();

Key Concepts Demonstrated

• sdkGetChunk — get or create a named chunk
• sdkChunkOperation — read/write chunk items with coAddOrModifyItem and coGetItem
• sdkChunkSubscribe — receive notifications when chunk data changes
• Flow types: ftDataFloat for float data, ftTextGeneral for text
• MSG_CHUNK_DESTROYED / MSG_CHUNK_ITEM_LIST_CHANGED — lifecycle notifications
• Cross-module data sharing via named chunks

SDK Callbacks Used

onGetModuleInfo · onGetNumberOfParams · onAfterQuery · onInitModule · onGetParamInfo · onCallBack

Related Examples

• GlobalArray — Simpler cross-module data sharing
• UsineObjects — Remote object access
• DrawTrajectoryBox — Module-local chunk persistence

SDK Reference

• UserModuleBase Class