684761db46
git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@22915 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775
102 lines
3.6 KiB
TeX
102 lines
3.6 KiB
TeX
\section{\class{wxThreadHelper}}\label{wxthreadhelper}
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The wxThreadHelper class is a mix-in class that manages a single background
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thread. By deriving from wxThreadHelper, a class can implement the thread
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code in its own \helpref{wxThreadHelper::Entry}{wxthreadhelperentry} method
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and easily share data and synchronization objects between the main thread
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and the worker thread. Doing this prevents the awkward passing of pointers
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that is needed when the original object in the main thread needs to
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synchronize with its worker thread in its own wxThread derived object.
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For example, \helpref{wxFrame}{wxframe} may need to make some calculations
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in a background thread and then display the results of those calculations in
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the main window.
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Ordinarily, a \helpref{wxThread}{wxthread} derived object would be created
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with the calculation code implemented in
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\helpref{wxThread::Entry}{wxthreadentry}. To access the inputs to the
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calculation, the frame object would often to pass a pointer to itself to the
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thread object. Similiarly, the frame object would hold a pointer to the
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thread object. Shared data and synchronization objects could be stored in
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either object though the object without the data would have to access the
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data through a pointer.
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However, with wxThreadHelper, the frame object and the thread object are
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treated as the same object. Shared data and synchronization variables are
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stored in the single object, eliminating a layer of indirection and the
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associated pointers.
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\wxheading{Derived from}
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None.
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\wxheading{Include files}
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<wx/thread.h>
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\wxheading{See also}
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\helpref{wxThread}{wxthread}, \helpref{wxThreadHelperThread}{wxthreadhelperthread}
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\latexignore{\rtfignore{\wxheading{Members}}}
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\membersection{wxThreadHelper::wxThreadHelper}\label{wxthreadhelperctor}
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\func{}{wxThreadHelper}{\void}
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This constructor simply initializes a member variable.
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\membersection{wxThreadHelper::m\_thread}
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\member{wxThread *}{m\_thread}
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the actual \helpref{wxThread}{wxthread} object.
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\membersection{wxThread::\destruct{wxThreadHelper}}
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\func{}{\destruct{wxThreadHelper}}{\void}
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The destructor frees the resources associated with the thread.
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\membersection{wxThreadHelper::Create}\label{wxthreadhelpercreate}
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\func{wxThreadError}{Create}{\param{unsigned int }{stackSize = 0}}
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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{GetThread()->Run()}{wxthreadrun} to start running
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it. You may optionally specify the stack size to be allocated to it (Ignored on
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platforms that don't support setting it explicitly, eg. Unix).
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\wxheading{Return value}
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One of:
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\twocolwidtha{7cm}
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\begin{twocollist}\itemsep=0pt
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\twocolitem{{\bf wxTHREAD\_NO\_ERROR}}{There was no error.}
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\twocolitem{{\bf wxTHREAD\_NO\_RESOURCE}}{There were insufficient resources to create a new thread.}
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\twocolitem{{\bf wxTHREAD\_RUNNING}}{The thread is already running.}
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\end{twocollist}
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\membersection{wxThreadHelper::Entry}\label{wxthreadhelperentry}
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\func{virtual ExitCode}{Entry}{\void}
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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
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joinable threads and is the value returned by
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\helpref{GetThread()->Wait()}{wxthreadwait}.
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This function is called by wxWindows itself and should never be called
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directly.
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\membersection{wxThreadHelper::GetThread}\label{wxthreadhelpergetthread}
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\func{wxThread *}{GetThread}{\void}
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This is a public function that returns the \helpref{wxThread}{wxthread} object
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associated with the thread.
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