Debugging and Exceptions classes

What are Exception Classes in Active Template Library?

Exception handling in C++ allows you to deal with unforeseen situations, such as runtime problems. As a result, if an unexpected event happens, program control is handed to unique routines called handlers. We put a particular portion of code under exception inspection to catch the exceptions.

In Active Template Library, there is a class called CAtlException. This class defines an ATL exception.

Syntax

class CAtlException

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Members

CAltException

Syntax

CAtlException::CAtlException
CAtlException(HRESULT hr) throw();
CAtlException() throw();

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It is the default public constructor to create an object of the CAltException Class.

HRESULT

Syntax

CAtlException::operator HRESULT
operator HRESULT() const throw ();

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It is a public operator and will cast the current object to an HRESULT value.

HRESULT stands for “Result Handle”. HRESULT is defined as a 32-bit signed integer value with several fields encoded in the value in the system header file. HRESULT returns success, warning, and error values. The value of HRESULT is set by the constructor CAltException.

M_hr

Syntax

CAtlException::m_hr
HRESULT m_hr;

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It is a Public data member, and It Creates a variable of the type HRESULT and is used to store the success, warming or error conditions.

Requirements

To use the CAltException class, you must include the atlexcept.h header file. 

An ATL operation-related exception condition is represented by a CAtlException object. 

The CAtlException class casts the exception that occurred into an HRESULT type that stores the status code of the exception that occurred.

Frequently Asked Questions

What is ATL?

ATL stands for Active Template Library. It is a set of template-based C++ classes developed by Microsoft to simplify the creation and programming of Component Object Model (COM) object called the ATL classes. 

What is Debugging?

Debugging is detecting and removing potential errors (also known as ‘bugs’), which,h if not handled, could cause the software to crash or behave unexpectedly. 

What is an Exception?

An exception is a condition that arises while a program is being executed and disturbs the normal flow of the program.

What is HRESULT in Active Template Library?

HRESULT Stands for “Result Handle”. The system header file defines HRESULT as a 32-bit signed integer value with numerous fields encoded in the value. HRESULT returns success, warning, and error values.

Conclusion

In this article, we discussed the Active Template Library offered by Microsoft. We discussed debugging and Exception handling and what features are provided by the Active Template Library to achieve the same.

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