Implement Qt log output to files

1. # Include <qtdebug>
2. # Include <qfile>
3. # Include <qtextstream
   >
5. Void custommessagehandler (qtmsgtype type, const char * MSG)
6. {
7. Qstring
   Txt;
8. Switch (type)
9. {
10. Case qtdebugmsg: // debugging information prompt
11. TXT = qstring ("Debug: % 1"). Arg (MSG );
12. Break;
13. Case qtwarningmsg: // general warning prompt
14. TXT = qstring ("Warning: % 1"). Arg (MSG );
15. Break;
16. Case QtCriticalMsg: // severe error message
17. Txt = QString ("Critical: % 1"). arg (msg );
18. Break;
19. Case QtFatalMsg: // fatal error prompt
20. Txt = QString ("Fatal: % 1"). arg (msg );
21. Abort ();
22. Default:
23. Break;
24. }
26. QFile outFile ("Log.txt ");
27. OutFile. open (QIODevice: WriteOnly | QIODevice: Append );
28. QTextStream ts (& outFile );
29. Ts <txt <endl;
30. }
32. Int main (int argc, char * argv [])
33. {
34. QApplication app (argc, argv );
36. // Register your MsgHandler first
37. QInstallMsgHandler (customMessageHandler );
39. // Logs can be directly written into the file as follows, and the log also contains time information.
40. QDebug ("This is a debug message at thisisqt.com ");
41. QWarning ("This is a warning message at thisisqt.com ");
42. QCritical ("This is a critical message at thisisqt.com ");
43. QFatal ("This is a fatal message at thisisqt.com ");
45. Return app.exe c ();
46. }

Above cited from http://www.thisisqt.com/forum/viewthread.php? Tid = 90