fortran子例程的Qt错误处理

Question

I have a Qt GUI project that calls a fortran subroutine from a C++ function. This fortran subroutine reads some data from a text file. But whenever the fortran code fails (eg bad integer in item list etc), the GUI window automatically closes. Is there a way to prevent it from closing if an error occures?

I tried using try-catch blocks like this

 try
 {
  // fortran function call
  test_();
 }
 catch(...)
 {
  qDebug()<<"Error";
 }

but it didn't work. Throwing exceptions with the throw statement does work however.

I also tried to subclass QApplication class and reimplement the notify() function:

   bool SafeApp::notify(QObject* obj,QEvent* event)
   {
   try
    {
     return QApplication::notify(obj,event);
    }
   catch(std::exception& e)
    {
     return false;
    }
   }

The code compiles and runs fine, but it still crashes after calling the fortran function.

Answer 1

Fortran does not have exceptions, so the Fortran function you're calling is not throwing anything that C++ can catch.

OTOH, in Fortran the default behavior for errors such as I/O errors is to stop the program. The GFortran runtime library uses the libc exit() or abort() functions for this, depending on what kind of error is encountered.

What you might be able to do, is to add IOSTAT= and/or IOMSG= specifiers to the Fortran I/O statements. In that case errors will cause a nonzero iostat and some message in the string pointed to by IOMSG rather than stopping the program.