MainThread

Forces task execution onto the main thread—the thread that called PowerPlant::start().

Syntax

on<Trigger<T>, MainThread>().then([](const T& data) {
    // Runs on the main thread
});

Behavior

MainThread is a Pool with a concurrency of 1 that exclusively uses the main thread. Only one MainThread task executes at a time. If the main thread is occupied, subsequent tasks queue until it becomes available.

Example

on<Trigger<RenderCommand>, MainThread>().then([](const RenderCommand& cmd) {
    // Guaranteed to run on the main thread
    glDrawArrays(...);
});

Notes

• The main thread is defined as the thread that called PowerPlant::start().
• Useful for APIs that require main-thread access (OpenGL, macOS AppKit, some GUI frameworks).

Warning

Scheduling too many `MainThread` tasks can create a bottleneck, since they execute sequentially on a single thread.

See Also

• Pool
• Sync