C++/Qt out of memory exceptions & handling

outofmemory.cpp

 QApplication app(argc, argv);
 ...
 try
 {
     app.exec();
 }
 catch (const std::bad_alloc &)
 {
     // clean up here, e.g. save the session
     // and close all config files.

     return 0; // exit the application
 }


//*******************OR*****************************************************//


 x = new (std::nothrow) X();      // Class X

 if (x == NULL)                   //or:  "if (x==0)", NULL pointer
 {
    // allocation failed
 }