Class Signal() Foundation

The Signal() function returns the class object for the Signal class, which implements a synchronization primitive based on event semaphores. A Signal object allows multiple threads or processes to coordinate their execution by signaling events and waiting for them to occur.

The Signal class provides a thread-safe mechanism for inter-thread communication where one or more threads can wait for an event to be signaled by another thread. When a signal is posted, all waiting threads are awakened. This pattern is useful for producer-consumer scenarios, thread coordination, and event-driven programming.

Key concepts:

- Event Semaphore: A synchronization object that can be in two states: signaled or non-signaled

- Signaling: Setting the semaphore to the signaled state, which releases waiting threads

- Waiting: Blocking thread execution until the semaphore becomes signaled

- Auto-reset: After a thread is released from waiting, the semaphore can be automatically reset to non-signaled state to ensure only one thread proceeds at a time

Use case scenarios:

1. Worker Thread Coordination: A main thread creates multiple worker threads that process data in parallel. Each worker signals completion using a Signal object. The main thread waits for all workers to complete before proceeding with result aggregation.

2. Event Notification System: A monitoring thread watches for file system changes or network events. When an event occurs, it signals waiting threads that are responsible for handling specific types of events, enabling responsive event-driven architecture.