59ef254318
This commit merges changes that were developed in the "racket7" repo. See that repo (which is no longer modified) for a more fine-grained change history. The commit includes experimental support for running Racket on Chez Scheme, but that "CS" variant is not built by default.
64 lines
2.3 KiB
Racket
64 lines
2.3 KiB
Racket
#lang scribble/doc
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@(require "utils.rkt"
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(for-label ffi/unsafe/os-thread))
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@title{Operating System Threads}
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@defmodule[ffi/unsafe/os-thread]{The
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@racketmodname[ffi/unsafe/os-thread] library provides functions for
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running constrained Racket code in a separate thread at the
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operating-system level. Except for @racket[os-thread-enabled?], the
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functions of @racketmodname[ffi/unsafe/os-thread] are currently
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supported only when @racket[(system-type 'vm)] returns
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@racket['chez-scheme], and even then only in certain build modes. The
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functions raise @racket[exn:fail:unsupported] when not supported.}
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@history[#:added "6.90.0.9"]
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@defproc[(os-thread-enabled?) boolean?]{
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Returns @racket[#t] if the other functions of
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@racketmodname[ffi/unsafe/os-thread] work without raising
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@racket[exn:fail:unsupported], @racket[#f] otherwise.}
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@defproc[(call-in-os-thread [thunk (-> any)]) void?]{
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Runs @racket[thunk] in a separate operating-system thread, which runs
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concurrently to all Racket threads.
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The @racket[thunk] is run in @tech{atomic mode}, and it must not
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inspect its continuation or use any Racket thread functions (such as
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@racket[thread] or @racket[current-thread]), any Racket
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synchronization functions (such as @racket[semaphore-post] or
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@racket[sync]), or any parameters (such as
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@racket[current-output-port]). Variables may be safely mutated with
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@racket[set!], and vectors, mutable pairs, boxes, mutable structure
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fields, and @racket[eq?]- and @racket[eqv?]-based hash tables can be
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mutated, but the visibility of mutations to other threads is
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unspecified except as synchronized through @racket[os-semaphore-wait]
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and @racket[os-semaphore-post].}
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@defproc[(make-os-semaphore) any]{
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Creates a semaphore that can be used with @racket[os-semaphore-wait]
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and @racket[os-semaphore-post] to synchronize an operating-system
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thread with Racket threads and other operating-system threads.}
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@defproc[(os-semaphore-post [sema any/c]) void?]{
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Analogous to @racket[semaphore-post], but posts to a semaphore created
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by @racket[make-os-semaphore].}
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@defproc[(os-semaphore-wait [sema any/c]) void?]{
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Analogous to @racket[semaphore-wait], but waits on a semaphore created
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by @racket[make-os-semaphore]. Waiting blocks the current thread; if
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the current thread is a Racket thread, then waiting also blocks all
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Racket threads.}
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