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1 \section{\class{wxThread}}\label{wxthread}
2
3 A thread is basically a path of execution through a program. Threads are also
4 sometimes called {\it light-weight processes}, but the fundamental difference
5 between threads and processes is that memory spaces of different processes are
6 separated while all threads share the same address space. While it makes it
7 much easier to share common data between several threads, it also makes much
8 easier to shoot oneself in the foot, so careful use of synchronization objects
9 such as \helpref{mutexes}{wxmutex} and/or \helpref{critical sections}{wxcriticalsection} is recommended.
10
11 \wxheading{Derived from}
12
13 None.
14
15 \wxheading{Include files}
16
17 <wx/thread.h>
18
19 \wxheading{See also}
20
21 \helpref{wxMutex}{wxmutex}, \helpref{wxCondition}{wxcondition}, \helpref{wxCriticalSection}{wxcriticalsection}
22
23 \latexignore{\rtfignore{\wxheading{Members}}}
24
25 \membersection{wxThread::wxThread}\label{wxthreadctor}
26
27 \func{}{wxThread}{\void}
28
29 Default constructor: it doesn't create nor starts the thread.
30
31 \membersection{wxThread::\destruct{wxThread}}
32
33 \func{}{\destruct{wxThread}}{\void}
34
35 wxThread destructor is private, so you can not call it directly - i.e., deleting
36 wxThread objects is forbidden. Instead, you should use \helpref{Delete}{wxthreaddelete} or
37 \helpref{Kill}{wxthreadkill} methods. This also means that thread objects should
38 eb {\bf always} allocated on the heap (i.e. with {\it new}) because the functions
39 mentioned above will try to reclaim the storage from the heap.
40
41 \membersection{wxThread::Create}\label{wxthreadcreate}
42
43 \func{wxThreadError}{Create}{\void}
44
45 Creates a new thread. The thread object is created in the suspended state, you
46 should call \helpref{Run}{wxthreadrun} to start running it.
47
48 \wxheading{Return value}
49
50 One of:
51
52 \twocolwidtha{7cm}
53 \begin{twocollist}\itemsep=0pt
54 \twocolitem{{\bf wxTHREAD\_NO\_ERROR}}{There was no error.}
55 \twocolitem{{\bf wxTHREAD\_NO\_RESOURCE}}{There were insufficient resources to create a new thread.}
56 \twocolitem{{\bf wxTHREAD\_RUNNING}}{The thread is already running.}
57 \end{twocollist}
58
59 \membersection{wxThread::Delete}\label{wxthreaddelete}
60
61 \func{void}{Delete}{\void}
62
63 This function should be called to terminate this thread. Unlike \helpref{Kill}{wxthreadkill}, it
64 gives the target thread the time to terminate gracefully. Because of this, however, this function
65 may not return immediately and if the thread is "hung" won't return at all. Also, message processing
66 is not stopped during this function execution, so the message handlers may be called from inside
67 it.
68
69 Delete() may be called for thread in any state: running, paused or even not yet created. Moreover,
70 it must be called if \helpref{Create}{wxthreadcreate} or \helpref{Run}{wxthreadrun} fail to free
71 the memory occupied by the thread object.
72
73 \membersection{wxThread::Entry}\label{wxthreadentry}
74
75 \func{virtual void *}{Entry}{\void}
76
77 This is the entry point of the thread. This function is pure virtual and must
78 be implemented by any derived class. The thread execution will start here.
79
80 The returned value is the thread exit code but is currently ignored in
81 wxWindows implementation (this will change in near future).
82
83 \membersection{wxThread::GetID}\label{wxthreadgetid}
84
85 \constfunc{unsigned long}{GetID}{\void}
86
87 Gets the thread identifier: this is a platform dependent number which uniquely identifies the
88 thread throughout the system during its existence (i.e. the thread identifiers may be reused).
89
90 \membersection{wxThread::GetPriority}\label{wxthreadgetpriority}
91
92 \constfunc{int}{GetPriority}{\void}
93
94 Gets the priority of the thread, between zero and 100.
95
96 The following priorities are already defined:
97
98 \twocolwidtha{7cm}
99 \begin{twocollist}\itemsep=0pt
100 \twocolitem{{\bf WXTHREAD\_MIN\_PRIORITY}}{0}
101 \twocolitem{{\bf WXTHREAD\_DEFAULT\_PRIORITY}}{50}
102 \twocolitem{{\bf WXTHREAD\_MAX\_PRIORITY}}{100}
103 \end{twocollist}
104
105 \membersection{wxThread::IsAlive}\label{wxthreadisalive}
106
107 \constfunc{bool}{IsAlive}{\void}
108
109 Returns TRUE if the thread is alive (i.e. started and not terminating).
110
111 \membersection{wxThread::IsMain}\label{wxthreadismain}
112
113 \constfunc{bool}{IsMain}{\void}
114
115 Returns TRUE if the calling thread is the main application thread.
116
117 \membersection{wxThread::IsPaused}\label{wxthreadispaused}
118
119 \constfunc{bool}{IsPaused}{\void}
120
121 Returns TRUE if the thread is paused.
122
123 \membersection{wxThread::IsRunning}\label{wxthreadisrunning}
124
125 \constfunc{bool}{IsRunning}{\void}
126
127 Returns TRUE if the thread is running.
128
129 \membersection{wxThread::Kill}\label{wxthreadkill}
130
131 \func{wxThreadError}{Kill}{\void}
132
133 Immediately terminates the target thread. {\bf This function is dangerous and should
134 be used with extreme care (and not used at all whenever possible)!} The resources
135 allocated to the thread will not be freed and the state of the C runtime library
136 may become inconsistent. Use \helpref{Delete()}{wxthreaddelete} instead.
137
138 \membersection{wxThread::OnExit}\label{wxthreadonexit}
139
140 \func{void}{OnExit}{\void}
141
142 Called when the thread exits. This function is called in the context of the thread
143 associated with the wxThread object, not in the context of the main thread.
144
145 \membersection{wxThread::Run}\label{wxthreadrun}
146
147 \func{wxThreadError}{Run}{\void}
148
149 Runs the thread.
150
151 \membersection{wxThread::SetPriority}\label{wxthreadsetpriority}
152
153 \func{void}{SetPriority}{\param{int}{ priority}}
154
155 Sets the priority of the thread, between zero and 100. This must be set before the thread is created.
156
157 The following priorities are already defined:
158
159 \twocolwidtha{7cm}
160 \begin{twocollist}\itemsep=0pt
161 \twocolitem{{\bf WXTHREAD\_MIN\_PRIORITY}}{0}
162 \twocolitem{{\bf WXTHREAD\_DEFAULT\_PRIORITY}}{50}
163 \twocolitem{{\bf WXTHREAD\_MAX\_PRIORITY}}{100}
164 \end{twocollist}
165
166 \membersection{wxThread::Sleep}\label{wxthreadsleep}
167
168 \func{\void}{Sleep}{\param{unsigned long }{milliseconds}}
169
170 Pauses the thread execution for the given amount of time.
171
172 This function should be used instead of \helpref{wxSleep}{wxsleep} by all worker
173 (i.e. all except the main one) threads.
174
175 \membersection{wxThread::This}\label{wxthreadthis}
176
177 \func{wxThread *}{This}{\void}
178
179 Return the thread object for the calling thread. NULL is returned if the calling thread
180 is the main (GUI) thread, but \helpref{IsMain}{wxthreadismain} should be used to test
181 whether the thread is really the main one because NULL may also be returned for the thread
182 not created with wxThread class. Generally speaking, the return value for such thread
183 is undefined.
184
185 \membersection{wxThread::Yield}\label{wxthreadyield}
186
187 \func{\void}{Yield}{\void}
188
189 Give the rest of the thread time slice to the system allowing the other threads to run.
190 See also \helpref{Sleep()}{wxthreadsleep}.
191