2011/10/4 Frank Church <vfclists at gmail.com>: > Is the purpose of DebugLn over write line its ability to write automatically > to a debug log text file? > See FAQ: http://wiki.lazarus.freepascal.org/Lazarus_Faq#How_can_I_see_debug_output.3F A writeln would crash a windows GUI application, that is the reason why debugln was invented. Vincent