how to catch unknown exception and print it

Question

hello to everyone, I have some program and everytime I run it, it throws exception and I don't know how to check what exactly it throws, so my question is, is it possible to catch exception and print it (I found rows which throws exception) thanks in advance

Answer 1

If it derives from std::exception you can catch by reference:

try
{
    // code that could cause exception
}
catch (const std::exception &exc)
{
    // catch anything thrown within try block that derives from std::exception
    std::cerr << exc.what();
}

But if the exception is some class that has is not derived from std::exception, you will have to know ahead of time it's type (i.e. should you catch std::string or some_library_exception_base).

You can do a catch all:

try
{
}
catch (...)
{
}

but then you can't do anything with the exception.

Answer 2

Can you elaborate what exact exception is thrown?

I suggest you identify why the exception is thrown and work towards preventing the exception from occuring.

Answer 3

Try as suggested by R Samuel Klatchko first. If that doesn't help, there's something else that might help:

a) Place a breakpoint on the exception type (handled or unhandled) if your debugger supports it.

b) On some systems, the compiler generates a call to an (undocumented?) function when a throw statement is executed. to find out, what function that is for your system, write a simple hello world program, that throws and catches an exception. start a debugger and place a breakpoint in the exceptions constructor, and see from where it is being called. the caling function is probably something like _throw(). afterwards, start the debugger again with the program you want to investigate as debuggee. place breakpoint on the function mentioned above (_throw or whatever) and run the program. when the exception is thrown, the debugger stops and you are right there to find out why.

Answer 4

If the same row throws an exception, it means there is a problem with your code. Remember exceptions should be exceptional and not an expected one.. And the program flow based on the exceptions is a poor practice.

The exceptions you were asking about new and delete might be due to the deletion of released memory, accessing a pointer that has been allocated no memory, etc., Take another look at your memory allocation and de-allocation..

Hope it helps..