1Thread(3) OCaml library Thread(3)
2
6 Thread - Lightweight threads for Posix 1003.1c and Win32.
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9 Module Thread
10
12 Module Thread
13 : sig end
14 Lightweight threads for Posix 1003.1c and Win32.
17 type t
23 The type of thread handles.
26 Thread creation and termination
31 val create : ('a -> 'b) -> 'a -> t
32 Thread.create funct arg creates a new thread of control, in which the
35 function application funct arg is executed concurrently with the other
36 threads of the program. The application of Thread.create returns the
37 handle of the newly created thread. The new thread terminates when the
38 application funct arg returns, either normally or by raising an un‐
39 caught exception. In the latter case, the exception is printed on
40 standard error, but not propagated back to the parent thread. Simi‐
41 larly, the result of the application funct arg is discarded and not di‐
42 rectly accessible to the parent thread.
43 val self : unit -> t
47 Return the handle for the thread currently executing.
49 val id : t -> int
53 Return the identifier of the given thread. A thread identifier is an
55 integer that identifies uniquely the thread. It can be used to build
56 data structures indexed by threads.
57 val exit : unit -> unit
61 Terminate prematurely the currently executing thread.
63 val kill : t -> unit
67 This function was supposed to terminate prematurely the thread whose
69 handle is given. It is not currently implemented due to problems with
70 cleanup handlers on many POSIX 1003.1c implementations. It always
71 raises the Invalid_argument exception.
72 Suspending threads
77 val delay : float -> unit
78 delay d suspends the execution of the calling thread for d seconds. The
81 other program threads continue to run during this time.
82 val join : t -> unit
86 join th suspends the execution of the calling thread until the thread
89 th has terminated.
90 val yield : unit -> unit
94 Re-schedule the calling thread without suspending it. This function
96 can be used to give scheduling hints, telling the scheduler that now is
97 a good time to switch to other threads.
98 Waiting for file descriptors or processes
103 The functions below are leftovers from an earlier, VM-based threading
104 system. The Unix module provides equivalent functionality, in a more
105 general and more standard-conformant manner. It is recommended to use
106 Unix functions directly.
107 val wait_read : Unix.file_descr -> unit
109 This function does nothing in the current implementation of the thread‐
111 ing library and can be removed from all user programs.
112 val wait_write : Unix.file_descr -> unit
116 This function does nothing in the current implementation of the thread‐
118 ing library and can be removed from all user programs.
119 val wait_timed_read : Unix.file_descr -> float -> bool
123 See Thread.wait_timed_write .
125 val wait_timed_write : Unix.file_descr -> float -> bool
129 Suspend the execution of the calling thread until at least one charac‐
131 ter or EOF is available for reading ( wait_timed_read ) or one charac‐
132 ter can be written without blocking ( wait_timed_write ) on the given
133 Unix file descriptor. Wait for at most the amount of time given as sec‐
134 ond argument (in seconds). Return true if the file descriptor is ready
135 for input/output and false if the timeout expired. The same function‐
136 ality can be achieved with Unix.select .
137 val select : Unix.file_descr list -> Unix.file_descr list ->
141 Unix.file_descr list -> float -> Unix.file_descr list * Unix.file_descr
142 list * Unix.file_descr list
143 Same function as Unix.select . Suspend the execution of the calling
145 thread until input/output becomes possible on the given Unix file de‐
146 scriptors. The arguments and results have the same meaning as for
147 Unix.select .
148 val wait_pid : int -> int * Unix.process_status
152 Same function as Unix.waitpid . wait_pid p suspends the execution of
154 the calling thread until the process specified by the process identi‐
155 fier p terminates. Returns the pid of the child caught and its termina‐
156 tion status, as per Unix.wait .
157 Management of signals
162 Signal handling follows the POSIX thread model: signals generated by a
163 thread are delivered to that thread; signals generated externally are
164 delivered to one of the threads that does not block it. Each thread
165 possesses a set of blocked signals, which can be modified using
166 Thread.sigmask . This set is inherited at thread creation time.
167 Per-thread signal masks are supported only by the system thread library
168 under Unix, but not under Win32, nor by the VM thread library.
169 val sigmask : Unix.sigprocmask_command -> int list -> int list
171 sigmask cmd sigs changes the set of blocked signals for the calling
174 thread. If cmd is SIG_SETMASK , blocked signals are set to those in
175 the list sigs . If cmd is SIG_BLOCK , the signals in sigs are added to
176 the set of blocked signals. If cmd is SIG_UNBLOCK , the signals in
177 sigs are removed from the set of blocked signals. sigmask returns the
178 set of previously blocked signals for the thread.
179 val wait_signal : int list -> int
183 wait_signal sigs suspends the execution of the calling thread until the
186 process receives one of the signals specified in the list sigs . It
187 then returns the number of the signal received. Signal handlers at‐
188 tached to the signals in sigs will not be invoked. The signals sigs
189 are expected to be blocked before calling wait_signal .
190OCamldoc 2021-07-22 Thread(3)