Exception Catching difference between VC++ and C#

[fischermx]

Exception Catching difference between VC++ and C#

In C# I have this:
try
{
int x, y, z;

x = 20;
y = 0;

z = x / y;
}
catch
{
Console.WriteLine("oops !");
}

And it nicely catches whatever error happens inside the try block.

But now in C++ I have this:
#include "stdafx.h"
#include <iostream>
using namespace std;

int main()
{
try
{
int x, y, z;

x = 20;
y = 0;

z = x / y;
}
catch(...)
{
cout << "Oops !";
}
}

And it blows. I get the windows dialog that tells me about sending the
error to Microsoft.
Why ?

[Ben Voigt]

<fi*******@gmail.comwrote in message
news:11********************@h3g2000cwc.googlegroup s.com...

Exception Catching difference between VC++ and C#

In C# I have this:
try
{
int x, y, z;

x = 20;
y = 0;

z = x / y;
}
catch
{
Console.WriteLine("oops !");
}

And it nicely catches whatever error happens inside the try block.

But now in C++ I have this:
#include "stdafx.h"
#include <iostream>
using namespace std;

int main()
{
try
{
int x, y, z;

x = 20;
y = 0;

z = x / y;
}
catch(...)
{
cout << "Oops !";
}
}

And it blows. I get the windows dialog that tells me about sending the
error to Microsoft.
Why ?

You aren't using a throw statement, but catching a hardware (asynchronous)
exception. The default (/EHsc) catches only synchronous (C++ language)
exceptions. Compile with /EHa.

[Doug Harrison [MVP]]

On 19 Feb 2007 13:10:31 -0800, fi*******@gmail.com wrote:

>Exception Catching difference between VC++ and C#

In C# I have this:
try
{
int x, y, z;

x = 20;
y = 0;

z = x / y;
}
catch
{
Console.WriteLine("oops !");
}

And it nicely catches whatever error happens inside the try block.

But now in C++ I have this:
#include "stdafx.h"
#include <iostream>
using namespace std;

int main()
{
try
{
int x, y, z;

x = 20;
y = 0;

z = x / y;
}
catch(...)
{
cout << "Oops !";
}
}

And it blows. I get the windows dialog that tells me about sending the
error to Microsoft.
Why ?

In C++, division by zero is undefined, and you should not expect any
particular treatment of the error. In Windows, integer division by zero
causes a structured exception, and VC++ allows you to catch it directly
with __try/__except or translate it into a C++ exception with
_set_se_translator. The latter requires you to compile with /EHa, and then
you will be able to catch it in catch(...). To understand why it's bad to
indiscriminately catch structured exceptions as C++ exceptions, see:

http://members.cox.net/doug_web/eh.htm

The C# language defines division by zero to throw
System.DivideByZeroException, and you can achieve much the same effect in
C++ by using _set_se_translator and turning EXCEPTION_INT_DIVIDE_BY_ZERO
into a C++ exception. Because you will also have to use /EHa, you should
stay away from catch(...) for the reasons given in my article. My
preference is to test for a zero denominator in the rare cases in which it
can occur. (For floating point, however, I might prefer to check the FPU
status word at the end of a calculation.)

--
Doug Harrison
Visual C++ MVP