try{}catch(...){} not working in Visual Studio 2012 C++

Question

1.00/5 (1 vote)

See more:

I've recently upgraded my code to compile in Visual Studio 2012 C++ from 2003. I know this may not be good form, but I tend to use a lot of try{}catch(...){} blocks rather than checking for NULL objects that could cause access violations. I didn't get any compile time errors, but in release mode rather than jumping to the catch(...){} block when such an error is encountered the application just crashes with the windows MyApp was forced to close window. Is this no longer supported? When I read the microsoft documentation:
http://msdn.microsoft.com/en-us/library/6dekhbbc(v=vs.110).aspx[^]

It doesn't give any indication that this syntax is no longer supported. Obviously I could update my code to get rid of this, but I'm bound to miss some instances and I'd rather avoid it if possible.

Thanks,
David

Posted 1-Apr-14 15:18pm

David Johns

Add a Solution

Comments

Sergey Alexandrovich Kryukov 1-Apr-14 22:52pm

Not enough information.

In certain sense, "a lot of try-catch" can be even worse than many checks for null. It means abuse and not understanding exceptions, which actually propagate across the stack and hence can be handled very rarely, only in some strategically selected points.

VC 2003 is just too old. Chances are, newer C++ works with your code correctly, and old C++ does not...

—SA

2 solutions

Add a Solution

Add your solution here

Treat my content as plain text, not as HTML

Preview 0

…

Existing Members

Sign in to your account

...or Join us

Download, Vote, Comment, Publish.

Your Email
Password
Forgot your password?

Your Email
This email is in use. Do you need your password?
Optional Password

I have read and agree to the Terms of Service and Privacy Policy
Please subscribe me to the CodeProject newsletters

When answering a question please:

Read the question carefully.
Understand that English isn't everyone's first language so be lenient of bad spelling and grammar.
If a question is poorly phrased then either ask for clarification, ignore it, or edit the question and fix the problem. Insults are not welcome.
Don't tell someone to read the manual. Chances are they have and don't get it. Provide an answer or move on to the next question.

Let's work to help developers, not make them feel stupid.

This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

User 59241 · Accepted Answer · 2014-04-01T16:51:00

Null pointer exceptions are not a part of c++.

You can however catch exceptions such as division by zero, access violation, etc. in Visual Studio using try -> catch (...) block by enabling /EHa option in project settings.

Modify Project Properties -> C/C++ -> Code Generation -> Modify the Enable C++ Exceptions to "Yes With SEH Exceptions".

Refer to:http://msdn.microsoft.com/en-us/library/1deeycx5%28v=vs.80%29.aspx[^]
This can be demonstrated using this code:

C++

#include <conio.h>
#include <iostream>

using namespace std;

void main(void)
{
  try {
        int* ptr = NULL;
        *ptr = 1;
    } catch (...) {
        cout << "Null pointer exception caught." << endl;
    }

	getch();
}

With SEH enabled an exception is caught otherwise not. There is a performance penalty to this approach.

David Johns · Accepted Answer · 2014-04-01T17:12:00

pwasser,

Great info. I suppose this exposed my ignorance. I was not aware that a null pointer exception was not generally caught.

Doing some more research based on your response I found this article:
http://www.gamedev.net/page/resources/_/technical/general-programming/the-visual-c-exception-model-r2488

Among other things, that article states:
"Assuming you want to make sure that catch (...) handles SEH exceptions, the process is relatively simple in MSVC: use the /EHa flag instead of /EHsc for enabling exception handling. For MSVC 7.1 and earlier, this prevents catch blocks from being removed by the optimizer, and is a necessary condition for the catch blocks doing so in MSVC 2005 and later."

I think that explains why my code caught these null pointer situations when complied in VS2003, but not in 2012.

The type of implementation I'm talking about is here:

C++

CString DBShipment::PackageType()
{
	try{
		return pOrder->pDB->settings.packageTypes[packageType].name;
	}catch(...){
	}

	return CString("");
}

In this function, I could do it more like this:

C++

CString DBShipment::PackageType()
{
	if(pOrder){
		if(pOrder->pDB){
			if(packageType>=0 && packageType<porder->pDB.settings.nPackageTypes){
				return pOrder->pDB->settings.packageTypes[packageType].name;
			}
		}
	}

	return CString("");
}

However, the solution I used successfully with VC++2003 was less verbose so I took the easy route.

What is still not clear to me. I could leave my code as is and enable the /EHa option to have the code work as I intended. The responses here as well as the article I referenced above say there is a performance downside of this. I wouldn't have expected that to be a big issue for what I am doing here. Any advice on whether to enable this option or switch all my implementations to the second approach I exemplified above?

try{}catch(...){} not working in Visual Studio 2012 C++

2 solutions

Solution 1

Solution 2

Add your solution here

Preview 0