- Qt 6.9
- Qt Core
- CMake Target Properties in Qt6 Core
- QT_WASM_PTHREAD_POOL_SIZE
- Qt 6.9.3 Reference Documentation

# QT_WASM_PTHREAD_POOL_SIZE

Internal WebAssembly thread pool size.

This property was introduced in Qt 6.2.4.

Note: This property is in technology preview and may change in future releases.

Note: This property is used only if targeting the WebAssembly platform.

Specifies the number of web workers (threads) to create at application startup. Qt allocates a pool size of 4 by default. This means the app can use 4 additional threads besides the main thread, without the additional overhead of creating a new web worker, which may deadlock if the main thread created it and join()s the thread without returning control to the event loop first. Translates into the Emscripten compiler setting of PTHREAD_POOL_SIZE.

For more information, see Pthreads support.