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1 | ///////////////////////////////////////////////////////////////////////////// | |
2 | // Name: msgqueue.h | |
3 | // Purpose: interface of wxMessageQueue<T> | |
4 | // Author: wxWidgets team | |
5 | // RCS-ID: $Id$ | |
6 | // Licence: wxWindows license | |
7 | ///////////////////////////////////////////////////////////////////////////// | |
8 | ||
9 | /** | |
10 | wxMessageQueue allows passing messages between threads. | |
11 | ||
12 | This class should be typically used to communicate between the main and worker | |
13 | threads. The main thread calls wxMessageQueue::Post and the worker thread | |
14 | calls wxMessageQueue::Receive. | |
15 | ||
16 | @tparam T | |
17 | For this class a message is an object of arbitrary type T. | |
18 | ||
19 | Notice that often there is a some special message indicating that the thread | |
20 | should terminate as there is no other way to gracefully shutdown a thread | |
21 | waiting on the message queue. | |
22 | ||
23 | @nolibrary | |
24 | @category{threading} | |
25 | ||
26 | @see wxThread | |
27 | */ | |
28 | template <typename T> | |
29 | class wxMessageQueue<T> | |
30 | { | |
31 | public: | |
32 | /** | |
33 | Default and only constructor. | |
34 | Use wxMessageQueue::IsOk to check if the object was successfully initialized. | |
35 | */ | |
36 | wxMessageQueue(); | |
37 | ||
38 | /** | |
39 | Returns @true if the object had been initialized successfully, @false | |
40 | if an error occurred. | |
41 | */ | |
42 | bool IsOk() const; | |
43 | ||
44 | /** | |
45 | Add a message to this queue and signal the threads waiting for messages | |
46 | (i.e. the threads which called wxMessageQueue::Receive or | |
47 | wxMessageQueue::ReceiveTimeout). | |
48 | ||
49 | This method is safe to call from multiple threads in parallel. | |
50 | */ | |
51 | wxMessageQueueError Post(T const& msg); | |
52 | ||
53 | /** | |
54 | Block until a message becomes available in the queue. | |
55 | Waits indefinitely long or until an error occurs. | |
56 | ||
57 | The message is returned in @a msg. | |
58 | */ | |
59 | wxMessageQueueError Receive(T& msg); | |
60 | ||
61 | /** | |
62 | Block until a message becomes available in the queue, but no more than | |
63 | @a timeout milliseconds has elapsed. | |
64 | ||
65 | If no message is available after @a timeout milliseconds then returns | |
66 | @b wxMSGQUEUE_TIMEOUT. | |
67 | ||
68 | If @a timeout is 0 then checks for any messages present in the queue | |
69 | and returns immediately without waiting. | |
70 | ||
71 | The message is returned in @a msg. | |
72 | */ | |
73 | wxMessageQueueError ReceiveTimeout(long timeout, T& msg); | |
74 | }; | |
75 |