Added wxCriticalSection::TryEnter() method.

This is similar to wxMutex::TryLock() and useful for the same reasons.

Closes #13638.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@69883 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/msw/thread.cpp

@@ -40,6 +40,8 @@
 
 #include "wx/except.h"
 
+#include "wx/dynlib.h"
+
 // must have this symbol defined to get _beginthread/_endthread declarations
 #ifndef _MT
     #define _MT
@@ -163,6 +165,25 @@ void wxCriticalSection::Enter()
     ::EnterCriticalSection((CRITICAL_SECTION *)m_buffer);
 }
 
+bool wxCriticalSection::TryEnter()
+{
+#if wxUSE_DYNLIB_CLASS
+    typedef BOOL
+      (WINAPI *TryEnterCriticalSection_t)(LPCRITICAL_SECTION lpCriticalSection);
+
+    static TryEnterCriticalSection_t
+        pfnTryEnterCriticalSection = (TryEnterCriticalSection_t)
+            wxDynamicLibrary(wxT("kernel32.dll")).
+                GetSymbol(wxT("TryEnterCriticalSection"));
+
+    return pfnTryEnterCriticalSection
+            ? (*pfnTryEnterCriticalSection)((CRITICAL_SECTION *)m_buffer) != 0
+            : false;
+#else
+    return false;
+#endif
+}
+
 void wxCriticalSection::Leave()
 {
     ::LeaveCriticalSection((CRITICAL_SECTION *)m_buffer);