| 1 | \section{\class{wxThreadHelper}}\label{wxthreadhelper} |
| 2 | |
| 3 | The wxThreadHelper class is a mix-in class that manages a single background |
| 4 | thread. By deriving from wxThreadHelper, a class can implement the thread |
| 5 | code in its own \helpref{wxThreadHelper::Entry}{wxthreadhelperentry} method |
| 6 | and easily share data and synchronization objects between the main thread |
| 7 | and the worker thread. Doing this prevents the awkward passing of pointers |
| 8 | that is needed when the original object in the main thread needs to |
| 9 | synchronize with its worker thread in its own wxThread derived object. |
| 10 | |
| 11 | For example, \helpref{wxFrame}{wxframe} may need to make some calculations |
| 12 | in a background thread and then display the results of those calculations in |
| 13 | the main window. |
| 14 | |
| 15 | Ordinarily, a \helpref{wxThread}{wxthread} derived object would be created |
| 16 | with the calculation code implemented in |
| 17 | \helpref{wxThread::Entry}{wxthreadentry}. To access the inputs to the |
| 18 | calculation, the frame object would often to pass a pointer to itself to the |
| 19 | thread object. Similarly, the frame object would hold a pointer to the |
| 20 | thread object. Shared data and synchronization objects could be stored in |
| 21 | either object though the object without the data would have to access the |
| 22 | data through a pointer. |
| 23 | |
| 24 | However, with wxThreadHelper, the frame object and the thread object are |
| 25 | treated as the same object. Shared data and synchronization variables are |
| 26 | stored in the single object, eliminating a layer of indirection and the |
| 27 | associated pointers. |
| 28 | |
| 29 | \wxheading{Derived from} |
| 30 | |
| 31 | None. |
| 32 | |
| 33 | \wxheading{Include files} |
| 34 | |
| 35 | <wx/thread.h> |
| 36 | |
| 37 | \wxheading{See also} |
| 38 | |
| 39 | \helpref{wxThread}{wxthread} |
| 40 | |
| 41 | \latexignore{\rtfignore{\wxheading{Members}}} |
| 42 | |
| 43 | \membersection{wxThreadHelper::wxThreadHelper}\label{wxthreadhelperctor} |
| 44 | |
| 45 | \func{}{wxThreadHelper}{\void} |
| 46 | |
| 47 | This constructor simply initializes a member variable. |
| 48 | |
| 49 | \membersection{wxThreadHelper::m\_thread}\label{wxthreadhelpermthread} |
| 50 | |
| 51 | \member{wxThread *}{m\_thread} |
| 52 | |
| 53 | the actual \helpref{wxThread}{wxthread} object. |
| 54 | |
| 55 | \membersection{wxThreadHelper::\destruct{wxThreadHelper}}\label{wxthreadhelperdtor} |
| 56 | |
| 57 | \func{}{\destruct{wxThreadHelper}}{\void} |
| 58 | |
| 59 | The destructor frees the resources associated with the thread. |
| 60 | |
| 61 | \membersection{wxThreadHelper::Create}\label{wxthreadhelpercreate} |
| 62 | |
| 63 | \func{wxThreadError}{Create}{\param{unsigned int }{stackSize = 0}} |
| 64 | |
| 65 | Creates a new thread. The thread object is created in the suspended state, and you |
| 66 | should call \helpref{GetThread()->Run()}{wxthreadrun} to start running |
| 67 | it. You may optionally specify the stack size to be allocated to it (Ignored on |
| 68 | platforms that don't support setting it explicitly, eg. Unix). |
| 69 | |
| 70 | \wxheading{Return value} |
| 71 | |
| 72 | One of: |
| 73 | |
| 74 | \twocolwidtha{7cm} |
| 75 | \begin{twocollist}\itemsep=0pt |
| 76 | \twocolitem{{\bf wxTHREAD\_NO\_ERROR}}{There was no error.} |
| 77 | \twocolitem{{\bf wxTHREAD\_NO\_RESOURCE}}{There were insufficient resources to create a new thread.} |
| 78 | \twocolitem{{\bf wxTHREAD\_RUNNING}}{The thread is already running.} |
| 79 | \end{twocollist} |
| 80 | |
| 81 | \membersection{wxThreadHelper::Entry}\label{wxthreadhelperentry} |
| 82 | |
| 83 | \func{virtual ExitCode}{Entry}{\void} |
| 84 | |
| 85 | This is the entry point of the thread. This function is pure virtual and must |
| 86 | be implemented by any derived class. The thread execution will start here. |
| 87 | |
| 88 | The returned value is the thread exit code which is only useful for |
| 89 | joinable threads and is the value returned by |
| 90 | \helpref{GetThread()->Wait()}{wxthreadwait}. |
| 91 | |
| 92 | This function is called by wxWidgets itself and should never be called |
| 93 | directly. |
| 94 | |
| 95 | \membersection{wxThreadHelper::GetThread}\label{wxthreadhelpergetthread} |
| 96 | |
| 97 | \func{wxThread *}{GetThread}{\void} |
| 98 | |
| 99 | This is a public function that returns the \helpref{wxThread}{wxthread} object |
| 100 | associated with the thread. |
| 101 | |