98 lines
4.9 KiB
OCaml
98 lines
4.9 KiB
OCaml
(***********************************************************************)
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(* *)
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(* Objective Caml *)
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(* *)
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(* Xavier Leroy, projet Cristal, INRIA Rocquencourt *)
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(* *)
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(* Copyright 1996 Institut National de Recherche en Informatique et *)
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(* Automatique. Distributed only by permission. *)
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(* *)
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(***********************************************************************)
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(* $Id$ *)
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(* Module [Thread]: user-level lightweight threads *)
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type t
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(* The type of thread handles. *)
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(** Thread creation and termination *)
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val create : ('a -> 'b) -> 'a -> t
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(* [Thread.create funct arg] creates a new thread of control,
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in which the function application [funct arg]
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is executed concurrently with the other threads of the program.
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The application of [Thread.create]
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returns the handle of the newly created thread.
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The new thread terminates when the application [funct arg]
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returns, either normally or by raising an uncaught exception.
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In the latter case, the exception is printed on standard error,
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but not propagated back to the parent thread. Similarly, the
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result of the application [funct arg] is discarded and not
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directly accessible to the parent thread. *)
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val self : unit -> t
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(* Return the thread currently executing. *)
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external id : t -> int = "thread_id"
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(* Return the identifier of the given thread. A thread identifier
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is an integer that identifies uniquely the thread.
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It can be used to build data structures indexed by threads. *)
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val exit : unit -> unit
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(* Terminate prematurely the currently executing thread. *)
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val kill : t -> unit
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(* Terminate prematurely the thread whose handle is given. *)
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(** Suspending threads *)
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val delay: float -> unit
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(* [delay d] suspends the execution of the calling thread for
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[d] seconds. The other program threads continue to run during
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this time. *)
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val join : t -> unit
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(* [join th] suspends the execution of the calling thread
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until the thread [th] has terminated. *)
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val wait_read : Unix.file_descr -> unit
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val wait_write : Unix.file_descr -> unit
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(* Suspend the execution of the calling thread until at least
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one character is available for reading ([wait_read]) or
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one character can be written without blocking ([wait_write])
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on the given Unix file descriptor. *)
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val wait_timed_read : Unix.file_descr -> float -> bool
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val wait_timed_write : Unix.file_descr -> float -> bool
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(* Same as [wait_read] and [wait_write], but wait for at most
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the amount of time given as second argument (in seconds).
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Return [true] if the file descriptor is ready for input/output
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and [false] if the timeout expired. *)
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val wait_pid : int -> int * Unix.process_status
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(* [wait_pid p] suspends the execution of the calling thread
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until the Unix process specified by the process identifier [p]
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terminates. A pid [p] of [-1] means wait for any child.
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A pid of [0] means wait for any child in the same process group
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as the current process. Negative pid arguments represent
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process groups. Returns the pid of the child caught and
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its termination status, as per [Unix.wait]. *)
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(*--*)
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(* The following primitives provide the basis for implementing
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synchronization functions between threads. Their direct use is
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discouraged, as they are very low-level and prone to race conditions
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and deadlocks. The modules [Mutex], [Condition] and [Event]
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provide higher-level synchronization primitives. *)
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val critical_section: bool ref
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(* Setting this reference to [true] deactivate thread preemption
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(the timer interrupt that transfers control from thread to thread),
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causing the current thread to run uninterrupted until
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[critical_section] is reset to [false] or the current thread
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explicitely relinquishes control using [sleep], [delay],
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[wait_inchan] or [wait_descr]. *)
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val sleep : unit -> unit
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(* Suspend the calling thread until another thread reactivates it
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using [wakeup]. Just before suspending the thread,
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[critical_section] is reset to [false]. Resetting
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[critical_section] and suspending the calling thread is an
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atomic operation. *)
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val wakeup : t -> unit
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(* Reactivate the given thread. After the call to [wakeup],
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the suspended thread will resume execution at some future time. *)
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