+@page overview_thread Multithreading Overview
+
+@tableofcontents
+
+wxWidgets provides a complete set of classes encapsulating objects necessary in
+multi-threaded (MT) applications: the wxThread class itself and different
+synchronization objects: mutexes (see wxMutex) and critical sections (see
+wxCriticalSection) with conditions (see wxCondition). The thread API in
+wxWidgets resembles to POSIX1.c threads API (a.k.a. pthreads), although several
+functions have different names and some features inspired by Win32 thread API
+are there as well.
+
+These classes hopefully make writing MT programs easier and they also provide
+some extra error checking (compared to the native - be it Win32 or Posix -
+thread API), however it is still a non-trivial undertaking especially for large
+projects. Before starting an MT application (or starting to add MT features to
+an existing one) it is worth asking oneself if there is no easier and safer way
+to implement the same functionality. Of course, in some situations threads
+really make sense (classical example is a server application which launches a
+new thread for each new client), but in others it might be an overkill. On the
+other hand, the recent evolution of the computer hardware shows an important
+trend towards multi-core systems, which are better exploited using multiple
+threads (e.g. you may want to split a long task among as many threads as many
+CPU (cores) the system reports; see wxThread::GetCPUCount).
+
+To implement non-blocking operations @e without using multiple threads you have
+two possible implementation choices:
+
+- use wxIdleEvent (e.g. to perform a long calculation while updating a progress dialog)
+- do everything at once but call wxWindow::Update() or wxApp::YieldFor(wxEVT_CATEGORY_UI)
+ periodically to update the screen.
+
+If instead you choose to use threads in your application, please read the
+following section of this overview.
+
+@see wxThread, wxThreadHelper, wxMutex, wxCriticalSection, wxCondition,
+ wxSemaphore
+
+
+
+@section overview_thread_notes Important Notes for Multi-threaded Applications
+
+When writing a multi-threaded application, it is strongly recommended that
+<b>no secondary threads call GUI functions</b>. The design which uses one GUI
+thread and several worker threads which communicate with the main one using
+@b events is much more robust and will undoubtedly save you countless problems
+(example: under Win32 a thread can only access GDI objects such as pens,
+brushes, device contexts created by itself and not by the other threads).
+
+For communication between secondary threads and the main thread, you may use
+wxEvtHandler::QueueEvent or its short version ::wxQueueEvent. These functions
+have a thread-safe implementation so that they can be used as they are for
+sending events from one thread to another. However there is no built in method
+to send messages to the worker threads and you will need to use the available
+synchronization classes to implement the solution which suits your needs
+yourself. In particular, please note that it is not enough to derive your class
+from wxThread and wxEvtHandler to send messages to it: in fact, this does not
+work at all. You're instead encouraged to use wxThreadHelper as it greatly
+simplifies the communication and the sharing of resources.
+
+You should also look at the wxThread docs for important notes about secondary
+threads and their deletion.
+
+Last, remember that if wxEventLoopBase::YieldFor() is used directly or
+indirectly (e.g. through wxProgressDialog) in your code, then you may have both
+re-entrancy problems and also problems caused by the processing of events out
+of order. To resolve the last problem wxThreadEvent can be used: thanks to its
+implementation of the wxThreadEvent::GetEventCategory function wxThreadEvent
+classes in fact do not get processed by wxEventLoopBase::YieldFor() unless you
+specify the @c wxEVT_CATEGORY_THREAD flag.
+
+See also the @sample{thread} for a sample showing some simple interactions
+between the main and secondary threads.
+
+*/
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