96 lines
4.8 KiB
OCaml
96 lines
4.8 KiB
OCaml
(***********************************************************************)
|
|
(* *)
|
|
(* Caml Special Light *)
|
|
(* *)
|
|
(* Xavier Leroy, projet Cristal, INRIA Rocquencourt *)
|
|
(* *)
|
|
(* Copyright 1995 Institut National de Recherche en Informatique et *)
|
|
(* Automatique. Distributed only by permission. *)
|
|
(* *)
|
|
(***********************************************************************)
|
|
|
|
(* $Id$ *)
|
|
|
|
(* Module [Thread]: user-level lightweight threads *)
|
|
|
|
type t
|
|
(* The type of thread handles. *)
|
|
|
|
(** Thread creation and termination *)
|
|
|
|
val create : ('a -> 'b) -> 'a -> t
|
|
(* [new funct arg] creates a new thread of control, in which the
|
|
function application [funct arg] is executed concurrently
|
|
with the other threads of the program. The application of [new]
|
|
returns the handle of the newly created thread.
|
|
The new thread terminates when the application [funct arg]
|
|
returns, either normally or by raising an uncaught exception.
|
|
In the latter case, the exception is printed on standard error,
|
|
but not propagated back to the parent thread. Similarly, the
|
|
result of the application [funct arg] is discarded and not
|
|
directly accessible to the parent thread. *)
|
|
val self : unit -> t
|
|
(* Return the thread currently executing. *)
|
|
external id : t -> int = "thread_id"
|
|
(* Return the identifier of the given thread. A thread identifier
|
|
is an integer that identifies uniquely the thread.
|
|
It can be used to build data structures indexed by threads. *)
|
|
val exit : unit -> unit
|
|
(* Terminate prematurely the currently executing thread. *)
|
|
val kill : t -> unit
|
|
(* Terminate prematurely the thread whose handle is given. *)
|
|
|
|
(** Suspending threads *)
|
|
|
|
val delay: float -> unit
|
|
(* [delay d] suspends the execution of the calling thread for
|
|
[d] seconds. The other program threads continue to run during
|
|
this time. *)
|
|
val join : t -> unit
|
|
(* [join th] suspends the execution of the calling thread
|
|
until the thread [th] has terminated. *)
|
|
val wait_read : Unix.file_descr -> unit
|
|
val wait_write : Unix.file_descr -> unit
|
|
(* Suspend the execution of the calling thread until at least
|
|
one character is available for reading ([wait_read]) or
|
|
one character can be written without blocking ([wait_write])
|
|
on the given Unix file descriptor. *)
|
|
val wait_timed_read : Unix.file_descr -> float -> bool
|
|
val wait_timed_write : Unix.file_descr -> float -> bool
|
|
(* Same as [wait_read] and [wait_write], but wait for at most
|
|
the amount of time given as second argument (in seconds).
|
|
Return [true] if the file descriptor is ready for input/output
|
|
and [false] if the timeout expired. *)
|
|
val wait_pid : int -> unit
|
|
(* [wait_pid p] suspends the execution of the calling thread
|
|
until the Unix process specified by the process identifier [p]
|
|
terminates. A pid [p] of [-1] means wait for any child.
|
|
A pid of [0] means wait for any child in the same process group
|
|
as the current process. Negative pid arguments represent
|
|
process groups. *)
|
|
|
|
(*--*)
|
|
|
|
(* The following primitives provide the basis for implementing
|
|
synchronization functions between threads. Their direct use is
|
|
discouraged, as they are very low-level and prone to race conditions
|
|
and deadlocks. The modules [Mutex], [Condition] and [Event]
|
|
provide higher-level synchronization primitives. *)
|
|
|
|
val critical_section: bool ref
|
|
(* Setting this reference to [true] deactivate thread preemption
|
|
(the timer interrupt that transfers control from thread to thread),
|
|
causing the current thread to run uninterrupted until
|
|
[critical_section] is reset to [false] or the current thread
|
|
explicitely relinquishes control using [sleep], [delay],
|
|
[wait_inchan] or [wait_descr]. *)
|
|
val sleep : unit -> unit
|
|
(* Suspend the calling thread until another thread reactivates it
|
|
using [wakeup]. Just before suspending the thread,
|
|
[critical_section] is reset to [false]. Resetting
|
|
[critical_section] and suspending the calling thread is an
|
|
atomic operation. *)
|
|
val wakeup : t -> unit
|
|
(* Reactivate the given thread. After the call to [wakeup],
|
|
the suspended thread will resume execution at some future time. *)
|