# spawnOn

## Category
Concurrency

## Arity
**Unary** or **Binary**.

```
// Unary: spawn on named scheduler
spawnOn ["schedulerName", { code }]

// Binary: with args
<args> spawnOn ["schedulerName", { code }]
```

## Description
Spawns code on a **specific named scheduler**, rather than the current one. This enables cross-scheduler work distribution — e.g., running AI on a dedicated "AI" scheduler while keeping the "Main" scheduler responsive.

Returns a `ScriptHandle` owned by the current scheduler.

## How It Works
1. Looks up the scheduler by name.
2. Creates a new fiber on that scheduler.
3. Passes arguments (if binary form) into the fiber.
4. Returns a handle visible to the calling scheduler.

The code runs with the target scheduler's budget and fiber management. Suspension (`sleep`, `await`) works normally inside the spawned code.

## Usage

### Unary spawnOn
```sqf
_handle = spawnOn ["AI", {
    heavyPathfinding();
    sleep 0.1;
    heavyPathfinding();
}];
```

### Binary spawnOn (with args)
```sqf
[enemyData] spawnOn ["AI", {
    params ["_data"];
    calculateBehavior(_data);
}];
```

### Work distribution pattern
```sqf
// Main scheduler: UI, input
// "AI" scheduler: pathfinding, behavior
// "Physics" scheduler: collision, movement

for "_i" from 1 to 10 do {
    _aiUnits pushBack (spawnOn ["AI", { aiLoop(); }]);
};
```

### Monitor spawned code
```sqf
_handle = spawnOn ["Worker", { longTask(); }];
_result = await (_handle timeout 30);
if (isNil "_result") then {
    terminate _handle;
    systemChat "Worker task timed out";
};
```

## Thread Safety
The spawned code runs on a **different** scheduler — thread safety rules apply. Data shared between schedulers must be [frozen](freeze.md), sent via [sendTo](sendTo.md), or use [shared](shared.md) variables.

## See Also
- [spawn](spawn.md) — spawn on current scheduler
- [currentScheduler](currentScheduler.md) — get current scheduler ID
- [schedulerName](schedulerName.md) — get scheduler name
- [sendTo](sendTo.md) — transfer data to scheduler
- [freeze](freeze.md) — make array safe for sharing