Exception-catching Error with Qt

[Crc]

I'm Japanese, so I'll maybe write wrong English.

I have a question.
I cannot throw exceptions on Qt.
For example, I attempted this code.

namespace Test{
 
          class ExceptionEx; // Class which is inherited std::exception
          // It, class ExceptionEx, is defined on another cpp file
 
          class Class1{
          public:
               Class1() throw(ExceptionEx);
          };
 
          Class1::Class1() throw(ExceptionEx){
                  throw ExceptionEx( "exception" );
          }
 
          void func( void ){
               try{
                        Class1 obj;
               }catch( ExceptionEx &e ){
                        // print exception-string out
               }
          }
}
 
class CMain{
public:
     CMain(){ this->createInstances(); this->setup(); } // To create widgets and other objects
     ... // omit...
protected:
     void createInstances( void ){
          // creating...
     }
 
     void setup( void ){
          ... // setup for widgets
          Test::func(); // <- This line is wrong. It crashes.
     }
private:
     // member variables omitted...
};

namespace Test{
          
          class ExceptionEx; // Class which is inherited std::exception
          // It, class ExceptionEx, is defined on another cpp file
          
          class Class1{
          public:
               Class1() throw(ExceptionEx);
          };
          
          Class1::Class1() throw(ExceptionEx){
                  throw ExceptionEx( "exception" );
          }
          
          void func( void ){
               try{
                        Class1 obj;
               }catch( ExceptionEx &e ){
                        // print exception-string out
               }
          }
}

class CMain{
public:
     CMain(){ this->createInstances(); this->setup(); } // To create widgets and other objects
     ... // omit...
protected:
     void createInstances( void ){
          // creating...
     }
     
     void setup( void ){
          ... // setup for widgets
          Test::func(); // <- This line is wrong. It crashes.
     }
private:
     // member variables omitted...
};

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The program crashed when I call the function Test::func.

Cannot we throw exceptions on Qt?

I have libraries for me, link it and the Boost.
If we cannot throw exceptions on Qt, I cannot use Qt...

Strictly speaking, cannot we *catch* exceptions with Qt?

[ChrisW67]

Your question (and code) have nothing to do with Qt. Using the Qt library does not change the handling of C++ exceptions. The following code based on yours does not crash and outputs "Failed" here (GCC 6.4, nothing to do with Qt).

#include <iostream>
#include <exception>
 
namespace Test {
  class ExceptionEx: public std::exception
  { 
  public:
    explicit ExceptionEx(const char* message): msg_(message) { }
    explicit ExceptionEx(const std::string& message): msg_(message) {}
    virtual ~ExceptionEx() throw () {}
    virtual const char* what() const throw () { return msg_.c_str(); } 
  protected:
    std::string msg_;
  };
}
 
namespace Test{
 
          class ExceptionEx; // Class which is inherited std::exception
          // It, class ExceptionEx, is defined on another cpp file
 
          class Class1{
          public:
               Class1() throw(ExceptionEx);
          };
 
          Class1::Class1() throw(ExceptionEx){
                  throw ExceptionEx( "exception" );
          }
 
          void func( void ){
               try{
                        Class1 obj;
               }catch( ExceptionEx &e ){
                        std::cout << "Failed" << std::endl;
               }
          }
}
 
int main(void)
{
    Test::func();
}

#include <iostream>
#include <exception>

namespace Test {
  class ExceptionEx: public std::exception
  { 
  public:
    explicit ExceptionEx(const char* message): msg_(message) { }
    explicit ExceptionEx(const std::string& message): msg_(message) {}
    virtual ~ExceptionEx() throw () {}
    virtual const char* what() const throw () { return msg_.c_str(); } 
  protected:
    std::string msg_;
  };
}

namespace Test{

          class ExceptionEx; // Class which is inherited std::exception
          // It, class ExceptionEx, is defined on another cpp file

          class Class1{
          public:
               Class1() throw(ExceptionEx);
          };

          Class1::Class1() throw(ExceptionEx){
                  throw ExceptionEx( "exception" );
          }

          void func( void ){
               try{
                        Class1 obj;
               }catch( ExceptionEx &e ){
                        std::cout << "Failed" << std::endl;
               }
          }
}

int main(void)
{
    Test::func();
}

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I suspect the crash is coming from elsewhere.

[Crc]

Thank you for your answer.

I had a mistake to send which I should do.

Real is...

https://pastebin.com/iepQ4pqQ

On the code, QtUse::QtWorker::CApplication is a class which derived QApplication,
QtUse::QtWindow::MainWindow is a class which derived QMainWindow...

Because they don't have event code.
So, I derived QMainWindow and create QtUse::QtWindow::MainWindow with event-processing.

You can read it as QMainWindow.

QtUse::QtMenu::Menu is composition with QMenu, QtUse::QtMenu::MenuItem is derived from QAction.

Thank you.