Add support for thread-specific log targets.

A worker thread can now have its own log target which will be used directly
by the log functions instead of buffering log output in the main thread; the
GUI thread in the thread sample shows how it works.


git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@61422 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/private/threadinfo.h

@@ -0,0 +1,43 @@
+///////////////////////////////////////////////////////////////////////////////
+// Name:        wx/private/threadinfo.h
+// Purpose:     declaration of wxThreadSpecificInfo: thread-specific information
+// Author:      Vadim Zeitlin
+// Created:     2009-07-13
+// RCS-ID:      $Id: wxhead.h,v 1.11 2009-06-29 10:23:04 zeitlin Exp $
+// Copyright:   (c) 2009 Vadim Zeitlin <vadim@wxwidgets.org>
+// Licence:     wxWindows licence
+///////////////////////////////////////////////////////////////////////////////
+
+#ifndef _WX_PRIVATE_THREADINFO_H_
+#define _WX_PRIVATE_THREADINFO_H_
+
+#if wxUSE_THREADS
+
+#include "wx/tls.h"
+
+class WXDLLIMPEXP_FWD_BASE wxLog;
+
+// ----------------------------------------------------------------------------
+// wxThreadSpecificInfo: contains all thread-specific information used by wx
+// ----------------------------------------------------------------------------
+
+// currently the only thread-specific information we use is the active wxLog
+// target but more could be added in the future (e.g. current wxLocale would be
+// a likely candidate) and we will group all of them in this struct to avoid
+// consuming more TLS slots than necessary as there is only a limited number of
+// them
+
+// NB: this must be a POD to be stored in TLS
+struct wxThreadSpecificInfo
+{
+    wxLog *logger;
+};
+
+// currently this is defined in src/common/log.cpp
+extern wxTLS_TYPE(wxThreadSpecificInfo) wxThreadInfoVar;
+#define wxThreadInfo wxTLS_VALUE(wxThreadInfoVar)
+
+#endif // wxUSE_THREADS
+
+#endif // _WX_PRIVATE_THREADINFO_H_
+