CodeGuru Home VC++ / MFC / C++ .NET / C# Visual Basic VB Forums Developer.com
Results 1 to 5 of 5

Thread: How to handle the exceptions that couldn't be caught by try/catch?

  1. #1
    Join Date
    Jul 2005
    Posts
    1,030

    How to handle the exceptions that couldn't be caught by try/catch?

    Here is an example,
    Code:
    int main()
    {
    	try{
    		int y = 0;
    		int x = 2/y;
    	}
    	catch(...)
    	{
    		cout<<"catch it"<<endl;
    	}
    	return 0;
    }
    If you try, you will find out that catch(...) couldn't catch exception divided by zero. How'd we catch such exceptions? Thanks.

  2. #2
    Join Date
    Jan 2006
    Location
    Singapore
    Posts
    6,768

    Re: How to handle the exceptions that couldn't be caught by try/catch?

    When there is division by zero, the behaviour is undefined. An implementation could make it such that an exception is thrown, but this would then be implementation specific, e.g., SEH exceptions, so you would need to check your compiler's documentation.
    C + C++ Compiler: MinGW port of GCC
    Build + Version Control System: SCons + Bazaar

    Look up a C/C++ Reference and learn How To Ask Questions The Smart Way
    Kindly rate my posts if you found them useful

  3. #3
    Join Date
    Apr 2000
    Location
    Belgium (Europe)
    Posts
    4,626

    Re: How to handle the exceptions that couldn't be caught by try/catch?

    some compilers have a specific (and different) synatx for handling SEH's. Typically, this type of handling can't be combined in the same function as regular C exception handling.

    Some compilers have wrappers so that a SEH will end up being thrown as a specific exception type, you may need to enable this via compiler switches.

    Some compilers will just wrap it in a generic untyped exception which you can catch with a catch(...), the bad thing here is that you typically don't know what type of exception it was. Again, this may need compiler switches to enable this.

    none of the above is standard. So you'll either lock yourself to a specific brand/type/version of compiler, or you'll need multiple conditional code paths to handle multiple compilers.

  4. #4
    Join Date
    Apr 1999
    Posts
    27,449

    Re: How to handle the exceptions that couldn't be caught by try/catch?

    Quote Originally Posted by LarryChen View Post
    If you try, you will find out that catch(...) couldn't catch exception divided by zero. How'd we catch such exceptions?
    Division by 0 is not a standard C++ exception, so there is nothing to "catch" since nothing is thrown.

    Regards,

    Paul McKenzie

  5. #5
    Join Date
    Apr 2000
    Location
    Belgium (Europe)
    Posts
    4,626

    Re: How to handle the exceptions that couldn't be caught by try/catch?

    Division by zero doesn't even have to be an exception at all.
    I have several platforms where a division by zero returns... 0.
    you may call that mathematically inaccurate, but in the bigger picture, the answer is just as (in)valid as an exception being thrown (which your C++ code may or may not be able to catch). THere's nothing in the C++ standard that says the above is an illegal result for a division by zero. There is a note in the C++ documentation that this happens because that's exactly how the processor itself does it since the processor doesn't support interrupts. So like said. "platform dependant".

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  


Windows Mobile Development Center


Click Here to Expand Forum to Full Width




On-Demand Webinars (sponsored)