wxThread docs updates

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@4713 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

docs/latex/wx/conditn.tex

@@ -1,6 +1,15 @@
 \section{\class{wxCondition}}\label{wxcondition}
 
-Condition class for code protection in multithreaded applications.
+wxCondition variables correspond to pthread conditions or to Win32 event
+objects. They may be used in a multithreaded application to wait until the
+given condition becomes true which happens when the condition becomes signaled.
+
+For example, if a worker thread is doing some long task and another thread has
+to wait until it's finished, the latter thread will wait on the condition
+object and the worker thread will signal it on exit (this example is not
+perfect because in this particular case it would be much better to just 
+\helpref{Wait()}{wxthreadwait} for the worker thread, but if there are several
+worker threads it already makes much more sense).
 
 \wxheading{Derived from}