Exception Handling in Visual C++

Visual C++ supports three kinds of exception handling:

(1) C++ exception handling

(2) Structured exception handling

(3) MFC exceptions

When to Use Exceptions 

Three categories of outcomes can occur when a function is called during program execution: normal execution, erroneous execution, or abnormal execution. Each category is described below.

  Normal execution 

The function may execute normally and return. Some functions return a result code to the caller, which indicates the outcome of the function. The possible result codes are strictly defined for the function and represent the range of possible outcomes of the function. The result code can indicate success or failure or can even indicate a particular type of failure that is within the normal range of expectations. For example, a file-status function can return a code that indicates that the file does not exist. Note that the term "error code" is not used because a result code represents one of many expected outcomes.

     Erroneous execution 

The caller makes some mistake in passing arguments to the function or calls the function in an inappropriate context. This situation causes an error, and it should be detected by an assertion during program development. 

Abnormal execution 

Abnormal execution includes situations where conditions outside the program's control, such as low memory or I/O errors, are influencing the outcome of the function. Abnormal situations should be handled by catching and throwing exceptions.

Exception class	Meaning
CMemoryException Class	Out-of-memory
CFileException Class	File exception
CArchiveException Class	Archive/Serialization exception
CNotSupportedException Class	Response to request for unsupported service
CResourceException Class	Windows resource allocation exception
CDaoException Class	Database exceptions (DAO classes)
CDBException Class	Database exceptions (ODBC classes)
COleException Class	OLE exceptions
COleDispatchException Class	Dispatch (automation) exceptions
CUserException Class	Exception that alerts the user with a message box, then throws a generic CException Class