C ++ Exception Handling

C ++ Exception Handling
C ++ Exception Handling

Translated from c ++ complete refrence 3rd Chapter 38

The standard c ++ library defines two exception-related libraries, <exception> and <stdexcept>. Exceptions are usually used to report errors.

<Exception>

<Exception> defines classes, declarations, and functions related to exception handling.

 

Class exception {

Public:

Exception () throw ();

Exception (const char * const &);

Exception (const char * const &, int );

Exception (const bad_exception & ob) throw ();

Virtual ~ Exception () throw ();

Exception & operator = (const exception & ob) throw ();

Virtual const char * what () const throw ();

};

Class bad_exception: public exception {

Public:

Bad_exception () throw ();

Bad_exception (const bad_exception & ob) throw ();

Virtual ~ Bad_exception () throw ();

Bad_exception & operator = (const bad_exception & ob) throw ();

Virtual const char * what () const throw ();

};

The exception class is the parent class of all exceptions in the c ++ library. The unexpected () function throws the bad_exception type. Each exception class overwrites what () to return a string that describes the exception.

Some important classes are inherited from the exception class. The first one is bad_alloc, Which is thrown when the new operation fails. The other is bad_typeid, Which is thrown when the typeid operation is used incorrectly.

<Exception> define the following declaration

Type	Definition
Terminate_handler	Typedef void (* terminate_handler )();
Unexpected_handler	Typedef void (* unexpected_handler )();

<Exception> define the following functions

Function	Description
Terminater_handler set_terminate (terminate_handler fn) throw ();	Specify the function called when the program ends. The old function pointer is returned.
Unexpected_handler set_unexpected (unexpected_handler fn) throw ();	Same as above.
Void terminate ();	This function is called when an exception is processed at the end. The default value is abort.
Void unexpected ();	Same as above

 

<Stdexcept>

<Stdexcept> defines some standard exception classes. There are two categories: logical errors and runtime errors. The running error is beyond the control of the programmer.

All logical errors are inherited from logic_error.

Exception	Description
Domain_error	Domain Error
Invalid_argument	Invalid Parameter
Length_error	Generally, the size of the created object is too large.
Out_of_range	Access to the outside world

Runtime errors are inherited from runtime_error

Exception	Description
Overflow_error	Overflow
Range_error	Beyond the indicated range
Underflow_error	Underflow