// Licence: wxWindows license
/////////////////////////////////////////////////////////////////////////////
+/*
+ NOTE: we explicitely don't name wxMutexGUIEnter() and wxMutexGUILeave()
+ as they're not safe. See also ticket #10366.
+*/
+
/**
@page overview_thread Multithreading
functions have different names and some features inspired by Win32 thread API
are there as well.
-These classes will 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
+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
+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 without using multiple threads you have
-two other possible implementation choices:
-- using wxIdleEvent (e.g. to perform a long calculation while updating a progress dialog)
-- simply do everything at once but call wxWindow::Update() periodically to update the screen.
+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.
-Even if there are the ::wxMutexGuiEnter and ::wxMutexGuiLeave functions which allows
-to use GUI functions from multiple threads, if you do decide to use threads in your
-application, it is strongly recommended that <b>no more than one calls GUI functions</b>.
+If instead you choose to use threads in your 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 MFC.
A workaround for some wxWidgets ports is calling wxMutexGUIEnter()
- before any GUI calls and then calling wxMutexGUILeave() afterwords. However,
- the recommended way is to simply process the GUI calls in the main thread
- through an event that is posted by wxQueueEvent().
+ before any GUI calls and then calling wxMutexGUILeave() afterwords.
+ However, the recommended way is to simply process the GUI calls in the main
+ thread through an event that is posted by wxQueueEvent().
This does not imply that calls to these classes are thread-safe, however,
as most wxWidgets classes are not thread-safe, including wxString.
*/
bool wxIsMainThread();
+
+
/**
This function must be called when any thread other than the main GUI thread
wants to get access to the GUI library. This function will block the
@endcode
This function is only defined on platforms which support preemptive
- threads.
+ threads and only works under some ports (wxMSW currently).
@note Under GTK, no creation of top-level windows is allowed in any thread
but the main one.