1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
|
/////////////////////////////////////////////////////////////////////////////
// Name: wx/msgqueue.h
// Purpose: interface of wxMessageQueue<T>
// Author: wxWidgets team
// Licence: wxWindows licence
/////////////////////////////////////////////////////////////////////////////
/**
Error codes for wxMessageQueue<> operations.
This enum contains the possible return value of wxMessageQueue<> methods.
@since 2.9.0
@category{threading}
*/
enum wxMessageQueueError
{
/// Indicates that the operation completed successfully.
wxMSGQUEUE_NO_ERROR = 0,
/**
Indicates that no messages were received before timeout expired.
This return value is only used by wxMessageQueue<>::ReceiveTimeout().
*/
wxMSGQUEUE_TIMEOUT,
/// Some unexpected (and fatal) error has occurred.
wxMSGQUEUE_MISC_ERROR
};
/**
wxMessageQueue allows passing messages between threads.
This class should be typically used to communicate between the main and worker
threads. The main thread calls wxMessageQueue::Post and the worker thread
calls wxMessageQueue::Receive.
@tparam T
For this class a message is an object of arbitrary type T.
Notice that often there is a some special message indicating that the thread
should terminate as there is no other way to gracefully shutdown a thread
waiting on the message queue.
@since 2.9.0
@nolibrary
@category{threading}
@see wxThread
*/
template <typename T>
class wxMessageQueue<T>
{
public:
/**
Default and only constructor.
Use wxMessageQueue::IsOk to check if the object was successfully initialized.
*/
wxMessageQueue();
/**
Remove all messages from the queue.
This method is meant to be called from the same thread(s) that call
Post() to discard any still pending requests if they became
unnecessary.
@since 2.9.1
*/
wxMessageQueueError Clear();
/**
Returns @true if the object had been initialized successfully, @false
if an error occurred.
*/
bool IsOk() const;
/**
Add a message to this queue and signal the threads waiting for messages
(i.e. the threads which called wxMessageQueue::Receive or
wxMessageQueue::ReceiveTimeout).
This method is safe to call from multiple threads in parallel.
*/
wxMessageQueueError Post(T const& msg);
/**
Block until a message becomes available in the queue.
Waits indefinitely long or until an error occurs.
The message is returned in @a msg.
*/
wxMessageQueueError Receive(T& msg);
/**
Block until a message becomes available in the queue, but no more than
@a timeout milliseconds has elapsed.
If no message is available after @a timeout milliseconds then returns
@b wxMSGQUEUE_TIMEOUT.
If @a timeout is 0 then checks for any messages present in the queue
and returns immediately without waiting.
The message is returned in @a msg.
*/
wxMessageQueueError ReceiveTimeout(long timeout, T& msg);
};
|
