module Thread:sig..end
Lightweight threads for Posix 1003.1c and Win32.
type 
The type of thread handles.
val create : ('a -> 'b) -> 'a -> tThread.create 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 Thread.create
   returns the handle of the newly created thread.
   The new thread terminates when the application funct arg
   returns, either normally or by raising the Thread.Exit exception
   or by raising any other uncaught exception.
   In the last case, the uncaught 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 -> tReturn the handle for the thread currently executing.
val id : t -> intReturn 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.
exception Exit
Exception that can be raised by user code to initiate termination
    of the current thread.
    Compared to calling the Thread.exit function, raising the
    Thread.Exit exception will trigger Fun.finally finalizers
    and catch-all exception handlers.
    It is the recommended way to terminate threads prematurely.
val exit : unit -> unitTerminate prematurely the currently executing thread.
val kill : t -> unitThis function was supposed to terminate prematurely the thread
    whose handle is given.  It is not currently implemented due to
    problems with cleanup handlers on many POSIX 1003.1c implementations.
    It always raises the Invalid_argument exception.
val delay : float -> unitdelay d suspends the execution of the calling thread for
   d seconds. The other program threads continue to run during
   this time.
val join : t -> unitjoin th suspends the execution of the calling thread
   until the thread th has terminated.
val yield : unit -> unitRe-schedule the calling thread without suspending it. This function can be used to give scheduling hints, telling the scheduler that now is a good time to switch to other threads.
The functions below are leftovers from an earlier, VM-based threading
    system.  The Unix module provides equivalent functionality, in
    a more general and more standard-conformant manner.  It is recommended
    to use Unix functions directly.
val wait_read : Unix.file_descr -> unitThis function does nothing in the current implementation of the threading library and can be removed from all user programs.
val wait_write : Unix.file_descr -> unitThis function does nothing in the current implementation of the threading library and can be removed from all user programs.
val wait_timed_read : Unix.file_descr -> float -> bool
val wait_timed_write : Unix.file_descr -> float -> boolSuspend the execution of the calling thread until at least
   one character or EOF is available for reading (wait_timed_read) or
   one character can be written without blocking (wait_timed_write)
   on the given Unix file descriptor. 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.
   The same functionality can be achieved with Unix.select.
val select : Unix.file_descr list ->
       Unix.file_descr list ->
       Unix.file_descr list ->
       float -> Unix.file_descr list * Unix.file_descr list * Unix.file_descr listSame function as Unix.select.
   Suspend the execution of the calling thread until input/output
   becomes possible on the given Unix file descriptors.
   The arguments and results have the same meaning as for
   Unix.select.
val wait_pid : int -> int * Unix.process_statusSame function as Unix.waitpid.
   wait_pid p suspends the execution of the calling thread
   until the process specified by the process identifier p
   terminates. Returns the pid of the child caught and
   its termination status, as per Unix.wait.
Signal handling follows the POSIX thread model: signals generated
  by a thread are delivered to that thread; signals generated externally
  are delivered to one of the threads that does not block it.
  Each thread possesses a set of blocked signals, which can be modified
  using Thread.sigmask.  This set is inherited at thread creation time.
  Per-thread signal masks are supported only by the system thread library
  under Unix, but not under Win32, nor by the VM thread library.
val sigmask : Unix.sigprocmask_command -> int list -> int listsigmask cmd sigs changes the set of blocked signals for the
   calling thread.
   If cmd is SIG_SETMASK, blocked signals are set to those in
   the list sigs.
   If cmd is SIG_BLOCK, the signals in sigs are added to
   the set of blocked signals.
   If cmd is SIG_UNBLOCK, the signals in sigs are removed
   from the set of blocked signals.
   sigmask returns the set of previously blocked signals for the thread.
val wait_signal : int list -> intwait_signal sigs suspends the execution of the calling thread
   until the process receives one of the signals specified in the
   list sigs.  It then returns the number of the signal received.
   Signal handlers attached to the signals in sigs will not
   be invoked.  The signals sigs are expected to be blocked before
   calling wait_signal.
val default_uncaught_exception_handler : exn -> unitThread.default_uncaught_exception_handler will print the thread's id,
    exception and backtrace (if available).
val set_uncaught_exception_handler : (exn -> unit) -> unitThread.set_uncaught_exception_handler fn registers fn as the handler
    for uncaught exceptions.
If the newly set uncaught exception handler raise an exception,
    Thread.default_uncaught_exception_handler will be called.