3.11.0-rc 3.10.0 (latest) 3.9.0 3.8.0 3.7.0 3.6.0 3.5.0 3.4.0 3.3.0 3.2.0 2.48.0-rc 2.47.1 2.46.0 2.45.0 2.44.0 2.43.0 2.42.0 2.41.0 2.40.0 2.39.0 2.38.0 2.37.0 2.36.0 2.35.0 2.34.0 2.33.0 2.32.0 2.31.0 2.30.0 2.29.0 2.28.0 2.27.0 2.26.0 2.25.1 2.24.0 2.23.0 2.22.1 2.21.0 2.20.0 2.19.0 2.18.0 2.17.0 2.16.0 2.15.1 2.14.0 2.13.0 2.12.0 2.11.0 2.10.1 The size of the background thread pool.
These threads are created by the client library to run a [`CompletionQueue`](https://docs.cloud.google.com/cpp/docs/reference/common/latest/classgoogle_1_1cloud_1_1CompletionQueue) which performs background work for gRPC.

> [!NOTE]
> **Note:** [`GrpcBackgroundThreadPoolSizeOption`](https://docs.cloud.google.com/cpp/docs/reference/common/latest/structgoogle_1_1cloud_1_1GrpcBackgroundThreadPoolSizeOption), [`GrpcCompletionQueueOption`](https://docs.cloud.google.com/cpp/docs/reference/common/latest/structgoogle_1_1cloud_1_1GrpcCompletionQueueOption), and [`GrpcBackgroundThreadsFactoryOption`](https://docs.cloud.google.com/cpp/docs/reference/common/latest/structgoogle_1_1cloud_1_1GrpcBackgroundThreadsFactoryOption) are mutually exclusive. This option will be ignored if either [`GrpcCompletionQueueOption`](https://docs.cloud.google.com/cpp/docs/reference/common/latest/structgoogle_1_1cloud_1_1GrpcCompletionQueueOption) or [`GrpcBackgroundThreadsFactoryOption`](https://docs.cloud.google.com/cpp/docs/reference/common/latest/structgoogle_1_1cloud_1_1GrpcBackgroundThreadsFactoryOption) are set.

## Type Aliases

### Type

**Alias Of** : `std::size_t`