Hi:

I have a rellly long process that produces about 700 Mb of a txt log output file. This is very hard to manage. So I want to divide the output in multiple smaller log files. This is what my main.cpp looks like

Qt Code: 
  1. #include <QtGui/QApplication>
  2. #include "mineedit.h"
  3. #include "logoutput.h"
  4. #include <iostream>
  5.  
  6. void messageHandling(QtMsgType type, const char *msg){
  7.  
  8.     if (ERRORLOGGER.isEmpty()){
  9.         ERRORLOGGER = DEFERRORLOGGER;
  10.     }
  11.  
  12.     std::cout << "In Message Handling" << std::endl;
  13.     std::cout << "Writing to file" << ERRORLOGGER.toStdString() << std::endl;
  14.  
  15.     QFile file(ERRORLOGGER);
  16.     file.open(QFile::Append);
  17.     QTextStream stream(&file);
  18.     switch (type) {
  19.     case QtDebugMsg:
  20.         stream << msg << "\n";
  21.         file.close();
  22.         break;
  23.     case QtWarningMsg:
  24.         stream << "WARNING: " << msg << "\n";
  25.         file.close();
  26.         break;
  27.     case QtCriticalMsg:
  28.         stream << "CRITICAL: " << msg << "\n";
  29.         file.close();
  30.         break;
  31.     case QtFatalMsg:
  32.         stream << "FATAL: " << msg << "\n";
  33.         file.close();
  34.         abort();
  35.     }    
  36. }
  37.  
  38. int main(int argc, char *argv[])
  39. {
  40.     ERRORLOGGER = DEFERRORLOGGER;
  41.     qInstallMsgHandler(messageHandling);
  42.     QApplication a(argc, argv);
  43.     MineEdit w;
  44.     w.show();
  45.     return a.exec();
  46. }
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And my logoutput.h is like
Qt Code: 
  1. #ifndef LOGOUTPUT_H
  2. #define LOGOUTPUT_H
  3.  
  4. #include <QString>
  5.  
  6. //----------------------------For outputting an error file--------------------------------
  7. #define         DEFERRORLOGGER             "/home/aarelovich/Documents/log.err"
  8. #define         FOLDER_OUTPUT_LOG          "./home/aarelovich/Documents"
  9. extern QString  ERRORLOGGER;
  10.  
  11. #endif // LOGOUTPUT_H
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Now in a part of my code I do:
ERRORLOGGER = name_of_current_log_file.

However I get the following compilation errors:
obj/main.o: In function `messageHandling(QtMsgType, char const*)':
/home/aarelovich/Dropbox/MineSim/main.cpp:8: undefined reference to `ERRORLOGGER'
/home/aarelovich/Dropbox/MineSim/main.cpp:9: undefined reference to `ERRORLOGGER'
/home/aarelovich/Dropbox/MineSim/main.cpp:13: undefined reference to `ERRORLOGGER'
/home/aarelovich/Dropbox/MineSim/main.cpp:15: undefined reference to `ERRORLOGGER'
obj/main.o: In function `main':
/home/aarelovich/Dropbox/MineSim/main.cpp:40: undefined reference to `ERRORLOGGER'
obj/mineedit.o:/home/aarelovich/Dropbox/MineSim/mineedit.cpp:101: more undefined references to `ERRORLOGGER' follow
collect2: ld returned 1 exit status

Can anyone please tell me what am I doing wrong? Or how I can dynamically change the output file in which I create my application log?

Thanks for any help