Exception%20Handling

1

• Exception Handling
• in

C
2

• Introduction
• Overview of C Exception Handling
• Designing With Exceptions
• Exception Handling Philosophies
• Conclusion

3

• Introduction

4

• Exception have been around in C for a while
  and are pretty common.

5

• Overview

6

• C Exception Handling is centered around the
  three keyword try, catch, and throw, the general
  purpose of which is to attempt to execute code
  and handle unexpected exceptional conditions.

7
For Example
8

• Simple code
• try
• if (! resourceAvail )
• throw MyExceptionClass(Resource Is Not
  Available)
• catch (MyExceptionClass myException)
• //resource was not available, do something
  cleanup
• throw

9

• Designing With Exceptions

10

• When implementing the packages which make up
  your applications, such as your core graphics
  engine, it is very useful to define an exceptions
  hierarchy to utilize. This is useful for
  delineating kinds of exceptions as well as
  translating error codes into useful string
  messages.

11

• A simple base class exception type can contain
  an error message string into which you can place
  your exceptions information. Specifying
  constructors which take parameters that specify
  the file and live number and a string message
  allows for an easy way of storing the origin of
  the exception.
• You can also put a simple method for logging the
  exceptions which can be called in the constructor
  of a concrete exception class.

12

• Exception Handling
• Philosophies

13
Three common reason for throwing an exception

• 1.  A programming error a pointer is null
  when it should not be
• 2.  A resource is not available for acquisition
  or release
• 3. A violation of a class invariant or a state
  of an object invariant -- a calculation that
  goes out of range.

14

• Conclusion

15

• Exception Handling is obviously a powerful
  feature of the C language.
• Exceptions can greatly simplify the development
  of a C package and provide the component writer
  a way to enforce the assumptions made when the
  component was implemented.

16

• Thank You