Corrected some typos and quaint English
git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@9648 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775
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@ -1,6 +1,6 @@
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\section{\class{wxThread}}\label{wxthread}
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A thread is basically a path of execution through a program. Threads are also
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A thread is basically a path of execution through a program. Threads are
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sometimes called {\it light-weight processes}, but the fundamental difference
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between threads and processes is that memory spaces of different processes are
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separated while all threads share the same address space. While it makes it
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@ -9,23 +9,23 @@ easier to shoot oneself in the foot, so careful use of synchronization objects
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such as \helpref{mutexes}{wxmutex} and/or \helpref{critical sections}{wxcriticalsection} is recommended.
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There are two types of threads in wxWindows: {\it detached} and {\it joinable}
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ones, just as in POSIX thread API (but unlike Win32 threads where all threads
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are joinable). The difference between the two is that only joinbale threads
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can return a return code - it is returned by Wait() function. The detached
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threads (default) can not be waited for.
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ones, just as in the POSIX thread API (but unlike Win32 threads where all threads
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are joinable). The difference between the two is that only joinable threads
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can return a return code - this is returned by the Wait() function. Detached
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threads (the default type) cannot be waited for.
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You shouldn't hurry to create all the threads joinable, however, because this
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has a disadvantage as well: you {\bf must} Wait() for a joinable thread of the
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system resources used by it will never be freed and you also must delete the
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corresponding wxThread object yourself, while detached threads are of the
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has a disadvantage as well: you {\bf must} Wait() for a joinable thread or the
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system resources used by it will never be freed, and you also must delete the
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corresponding wxThread object yourself. In contrast, detached threads are of the
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"fire-and-forget" kind: you only have to start a detached thread and it will
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terminate and destroy itself.
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This means, of course, that all detached threads {\bf must} be created on the
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heap because the thread will call {\tt delete this;} upon termination. The
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joinable threads may be created on stack (don't create global thread objects
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because they allocate memory in their constructor which is a badthing to do),
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although usually they will be created on the heap as well.
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heap because the thread will call {\tt delete this;} upon termination. Joinable
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threads may be created on the stack although more usually they will be created on the heap.
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Don't create global thread objects because they allocate memory in their constructor,
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which will cause problems for the memory checking system.
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\wxheading{Derived from}
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@ -45,11 +45,12 @@ None.
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\func{}{wxThread}{\param{wxThreadKind }{kind = wxTHREAD\_DETACHED}}
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Constructor creates a new detached (default) or joinable C++ thread object. It
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does not create (or starts execution of) the real thread - for this you should
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use \helpref{Create}{wxthreadcreate} and \helpref{Run}{wxthreadrun} methods.
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This constructor creates a new detached (default) or joinable C++ thread object. It
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does not create or start execution of the real thread - for this you should
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use the \helpref{Create}{wxthreadcreate} and \helpref{Run}{wxthreadrun} methods.
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The possible values for {\it kind} parameters are:
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\twocolwidtha{7cm}
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\begin{twocollist}\itemsep=0pt
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\twocolitem{{\bf wxTHREAD\_DETACHED}}{Create a detached thread.}
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@ -60,14 +61,13 @@ The possible values for {\it kind} parameters are:
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\func{}{\destruct{wxThread}}{\void}
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Destructor frees the ressources associated with the thread. Notice that you
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The destructor frees the resources associated with the thread. Notice that you
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should never delete a detached thread - you may only call
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\helpref{Delete}{wxthreaddelete} on it or wait until it terminates (and auto
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destructs) itself. Because the detached threads delete themselves, they can
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only be allocated on the heap.
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The joinable threads, however, may and should be deleted explicitly and
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\helpref{Delete}{wxthreaddelete} and \helpref{Kill}{wxthreadkill} functions
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Joinable threads should be deleted explicitly. The \helpref{Delete}{wxthreaddelete} and \helpref{Kill}{wxthreadkill} functions
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will not delete the C++ thread object. It is also safe to allocate them on
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stack.
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@ -75,7 +75,7 @@ stack.
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\func{wxThreadError}{Create}{\void}
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Creates a new thread. The thread object is created in the suspended state, you
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Creates a new thread. The thread object is created in the suspended state, and you
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should call \helpref{Run}{wxthreadrun} to start running it.
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\wxheading{Return value}
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@ -96,21 +96,21 @@ One of:
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Calling \helpref{Delete}{wxthreaddelete} is a graceful way to terminate the
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thread. It asks the thread to terminate and, if the thread code is well
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written, the thread will terminate after the next call to
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\helpref{TestDestroy}{wxthreadtestdestroy} which should happen quiet soon.
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\helpref{TestDestroy}{wxthreadtestdestroy} which should happen quite soon.
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However, if the thread doesn't call \helpref{TestDestroy}{wxthreadtestdestroy}
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often enough (or at all), the function will not return immediately, but wait
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until the thread terminates. As it may take a long time, the message processing
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is not stopped during this function execution, so the message handlers may be
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until the thread terminates. As it may take a long time, and the message processing
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is not stopped during this function execution, message handlers may be
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called from inside it!
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Delete() may be called for thread in any state: running, paused or even not yet
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created. Moreover, it must be called if \helpref{Create}{wxthreadcreate} or
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\helpref{Run}{wxthreadrun} failed for a detached thread to free the memory
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occupied by the thread object (it will be done in the destructor for joinable
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threads).
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occupied by the thread object. This cleanup will be done in the destructor for joinable
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threads.
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Delete() may be called for thread in any state: running, paused or even not yet created. Moreover,
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Delete() may be called for a thread in any state: running, paused or even not yet created. Moreover,
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it must be called if \helpref{Create}{wxthreadcreate} or \helpref{Run}{wxthreadrun} fail to free
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the memory occupied by the thread object. However, you should not call Delete()
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on a detached thread which already terminated - doing so will probably result
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@ -128,7 +128,7 @@ This function can only be called from another thread context.
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This is the entry point of the thread. This function is pure virtual and must
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be implemented by any derived class. The thread execution will start here.
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The returned value is the thread exit code which is only useful for the
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The returned value is the thread exit code which is only useful for
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joinable threads and is the value returned by \helpref{Wait}{wxthreadwait}.
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This function is called by wxWindows itself and should never be called
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@ -138,8 +138,8 @@ directly.
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\func{void}{Exit}{\param{ExitCode }{exitcode = 0}}
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This is a protected function of wxThread class and thus can be called only
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from a derived class. It also can be called only in the context of this
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This is a protected function of the wxThread class and thus can only be called
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from a derived class. It also can only be called in the context of this
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thread, i.e. a thread can only exit from itself, not from another thread.
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This function will terminate the OS thread (i.e. stop the associated path of
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@ -160,7 +160,7 @@ Returns the number of system CPUs or -1 if the value is unknown.
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\constfunc{unsigned long}{GetId}{\void}
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Gets the thread identifier: this is a platform dependent number which uniquely identifies the
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Gets the thread identifier: this is a platform dependent number that uniquely identifies the
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thread throughout the system during its existence (i.e. the thread identifiers may be reused).
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\membersection{wxThread::GetPriority}\label{wxthreadgetpriority}
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@ -188,7 +188,7 @@ Returns TRUE if the thread is alive (i.e. started and not terminating).
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\constfunc{bool}{IsDetached}{\void}
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Returns TRUE if the thread is of detached kind, FALSE if it is a joinable one.
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Returns TRUE if the thread is of the detached kind, FALSE if it is a joinable one.
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\membersection{wxThread::IsMain}\label{wxthreadismain}
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@ -217,18 +217,18 @@ be used with extreme care (and not used at all whenever possible)!} The resource
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allocated to the thread will not be freed and the state of the C runtime library
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may become inconsistent. Use \helpref{Delete()}{wxthreaddelete} instead.
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For detached threads Kill() will also delete the associated C++ object,
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however this will not happen for joinable threads and this means that you will
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For detached threads Kill() will also delete the associated C++ object.
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However this will not happen for joinable threads and this means that you will
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still have to delete the wxThread object yourself to avoid memory leaks.
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In neither case \helpref{OnExit}{wxthreadonexit} of the dying thread will be
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called, so no thread-specific cleanup will be performed.
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This function can only be called from another thread context, i.e. a thread
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can not kill itself.
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cannot kill itself.
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It is also an error to call this function for a thread which is not running or
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paused (in the latter case, the thread will be resumed first) - if you do it,
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{\tt wxTHREAD\_NOT\_RUNNING} error will be returned.
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a {\tt wxTHREAD\_NOT\_RUNNING} error will be returned.
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\membersection{wxThread::OnExit}\label{wxthreadonexit}
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@ -283,7 +283,7 @@ The following priorities are already defined:
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Pauses the thread execution for the given amount of time.
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This function should be used instead of \helpref{wxSleep}{wxsleep} by all worker
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(i.e. all except the main one) threads.
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threads (i.e. all except the main one).
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\membersection{wxThread::Resume}\label{wxthreadresume}
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@ -302,13 +302,13 @@ number of threads that the system tries to schedule to run in parallel.
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The value of $0$ for {\it level} may be used to set the default one.
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Returns TRUE on success or FALSE otherwise (for example, if this function is
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not implemented for this platform (currently everything except Solaris)).
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not implemented for this platform - currently everything except Solaris).
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\membersection{wxThread::TestDestroy}\label{wxthreadtestdestroy}
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\func{bool}{TestDestroy}{\void}
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This function should be periodically called by the thread to ensure that calls
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This function should be called periodically by the thread to ensure that calls
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to \helpref{Pause}{wxthreadpause} and \helpref{Delete}{wxthreaddelete} will
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work. If it returns TRUE, the thread should exit as soon as possible.
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@ -319,7 +319,7 @@ work. If it returns TRUE, the thread should exit as soon as possible.
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Return the thread object for the calling thread. NULL is returned if the calling thread
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is the main (GUI) thread, but \helpref{IsMain}{wxthreadismain} should be used to test
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whether the thread is really the main one because NULL may also be returned for the thread
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not created with wxThread class. Generally speaking, the return value for such thread
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not created with wxThread class. Generally speaking, the return value for such a thread
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is undefined.
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\membersection{wxThread::Yield}\label{wxthreadyield}
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