15.2 Semaphore

8.16.0.2

15.2 Semaphore🔗ℹ

A semaphore is a synchronizable event that has an internal counter. Posting to a semaphore increments its counter, and waiting on a semaphore blocks until the counter is positive and can be decremented. As a synchronizable event, a semaphore is ready for synchronization when its counter is positive; the synchronization result is just the semaphore itself.

class

class Semaphore():

constructor (init :: NonnegInt = 0)

Constructs a semaphore that initially has init Semaphore.post actions.

A Semaphore object satisfies Evt and includes the Evt.sync method.

method

method (sema :: Semaphore).post() :: Void

method

method (sema :: Semaphore).wait() :: Void

method

method (sema :: Semaphore).poll() :: Boolean

Posts, waits, or polls a semaphore. When Semaphore.poll successfully waits on a semaphore, it returns #true, otherwise it returns #false.

property

property (sema :: Semaphore).handle

function

fun Semaphore.from_handle(handle) :: Semaphore

The Semaphore.handle property accesses a semaphore object’s underlying Racket representation. The Semaphore.from_handle function constructs a Rhombus semaphore object from a Racket semaphore object.

1	Notation and Conventions
2	Implicits and Context
3	Names and Definitions
4	Functions and Operators
5	Comparison and Branching
6	Objects and Annotations
7	Basic Data
8	Collections and Iteration
9	Object Protocols
10	Higher-Order Control
11	Code as Data
12	String Formatting and Matching
13	Input and Output
14	Operating System
15	Threads and Concurrency
16	Reflection and Security
17	Runtime System
18	Meta and Macros

15.1	Threads
15.2	Semaphore
15.3	Synchronizable Events