Added a note about cFont::GetFont() not being thread-safe

HISTORY

@@ -6075,7 +6075,7 @@ Video Disk Recorder Revision History
 - cFrameDetector::Analyze() now syncs on the TS packet sync bytes (thanks to
   Oliver Endriss for reporting broken index generation after a buffer overflow).
 
-2009-05-21: Version 1.7.8
+2009-05-23: Version 1.7.8
 
 - Fixed a typo in aspect ratio 2.21:1 (reported by Reinhard Nissl).
 - The name of the function cDevice::GetVideoSize() wasn't very well chosen
@@ -6108,3 +6108,4 @@ Video Disk Recorder Revision History
 - The new setup option "Recording/Pause key handling" can be used to define
   what happens if the Pause key on the remote control is pressed during
   live tv (thanks to Timo Eskola).
+- Added a note about cFont::GetFont() not being thread-safe.

font.h

@@ -4,7 +4,7 @@
  * See the main source file 'vdr.c' for copyright information and
  * how to reach the author.
  *
- * $Id: font.h 2.1 2009/05/03 11:00:19 kls Exp $
+ * $Id: font.h 2.2 2009/05/23 10:10:40 kls Exp $
  */
 
 #ifndef __FONT_H
@@ -55,9 +55,11 @@ public:
   static const cFont *GetFont(eDvbFont Font);
           ///< Gets the given Font, which was previously set by a call to SetFont().
           ///< If no SetFont() call has been made, the font as defined in the setup is returned.
-          ///< The caller must not use the returned font outside the scope in which
-          ///< it was retrieved by the call to GetFont(), because a call to SetFont()
-          ///< may delete an existing font.
+          ///< GetFont() is not thread-safe, and shall only be called from the main
+          ///< thread! A font returned by GetFont() must only be used locally inside the
+          ///< function it was retrieved from, and no long term pointer to it shall be kept,
+          ///< because the cFont object may become invalid at any time after the
+          ///< function that called GetFont() has returned.
   static cFont *CreateFont(const char *Name, int CharHeight, int CharWidth = 0);
           ///< Creates a new font object with the given Name and makes its characters
           ///< CharHeight pixels high. If CharWidth is given, it overwrites the font's