139 lines
5.8 KiB
OCaml
139 lines
5.8 KiB
OCaml
(***********************************************************************)
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(* *)
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(* OCaml *)
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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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(* en Automatique. All rights reserved. This file is distributed *)
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(* under the terms of the GNU Library General Public License, with *)
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(* the special exception on linking described in file ../../LICENSE. *)
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(* *)
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(***********************************************************************)
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(** Lightweight threads. *)
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type t
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(** The type of thread handles. *)
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(** {6 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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val id : t -> int
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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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This functionality is available only with bytecode-level threads. *)
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(** {6 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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(** See {!Thread.wait_write}.*)
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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 ({!Thread.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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(** See {!Thread.wait_timed_write}.*)
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val wait_timed_write : Unix.file_descr -> float -> bool
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(** Same as {!Thread.wait_read} and {!Thread.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 select :
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Unix.file_descr list -> Unix.file_descr list -> Unix.file_descr list ->
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float ->
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Unix.file_descr list * Unix.file_descr list * Unix.file_descr list
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(** Suspend the execution of the calling thead until input/output
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becomes possible on the given Unix file descriptors.
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The arguments and results have the same meaning as for
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{!Unix.select}. *)
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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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val wait_signal : int list -> int
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(** [wait_signal sigs] suspends the execution of the calling thread
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until the process receives one of the signals specified in the
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list [sigs]. It then returns the number of the signal received.
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Signal handlers attached to the signals in [sigs] will not
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be invoked. Do not call [wait_signal] concurrently
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from several threads on the same signals. *)
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val yield : unit -> unit
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(** Re-schedule the calling thread without suspending it.
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This function can be used to give scheduling hints,
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telling the scheduler that now is a good time to
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switch to other threads. *)
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(**/**)
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(** {6 Synchronization primitives}
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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 {!Thread.wakeup}. Just before suspending the thread,
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{!Thread.critical_section} is reset to [false]. Resetting
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{!Thread.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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