Question

I have defined a simple int error code:

#define my_error 20

Somewhere in my code I throw this error:

throw my_error;

Now I want to try and catch this exception thrown:

try
{
    ...
    ...
}
catch (my_error)
{
    cout << "Error: my error";
}

Unfortunately the compiler doesn’t approve this:

• syntax error : ‘constant’
• catch handlers must specify one type
• ‘try’ block starting on line ’34’ has no catch handlers

Is there a way to do this?

Answer 1

20 is not a type, so you can’t catch it. What you can do is filter the values in the catch block:

catch (int exception)
{
    if ( exception == 20 )
        cout << "Error: my error";
}

An even better approach would be to define your own exception:

class MyException : public std::exception
{
}

//...

try
{
   throw MyException();
}
catch(MyException& ex)
{
}