Solved

const volatile variable

Posted on 1998-09-16
2
821 Views
Last Modified: 2008-02-01
Hi friends,
        can anyone please say me where a constant volatile variable will be used?.
Thanks.
0
Comment
Question by:66
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
2 Comments
 
LVL 5

Expert Comment

by:ecw
ID: 1172859
maybe a read only device register!
0
 

Accepted Solution

by:
euclid091498 earned 0 total points
ID: 1172860
A variable modified with both const and volatile will be affected by both:

- Because it is const, the compiler will not allow it to be modified BY THE CODE after it is initialized.
- Because it is volatile, the compiler will not attempt agressive optimizations that might depend on the content not being modified EXTERNALLY.

There is an example given in 'The C++ Programming Language" (p 808, 3rd edition):

extern const volatile clock;

"Two successive reads of clock might give different results."
So it is declared volatile.
It is also declared const so that it will not be possible to modify it IN THE CODE.

0

Featured Post

Technology Partners: We Want Your Opinion!

We value your feedback.

Take our survey and automatically be enter to win anyone of the following:
Yeti Cooler, Amazon eGift Card, and Movie eGift Card!

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Suggested Solutions

Title # Comments Views Activity
Problem with SqlConnection 4 194
Path to  STL Map header file 1 91
Error C2678: binary '!=': no operator found... 4 73
No module found pypyodbc, 3 58
Unlike C#, C++ doesn't have native support for sealing classes (so they cannot be sub-classed). At the cost of a virtual base class pointer it is possible to implement a pseudo sealing mechanism The trick is to virtually inherit from a base class…
This article shows you how to optimize memory allocations in C++ using placement new. Applicable especially to usecases dealing with creation of large number of objects. A brief on problem: Lets take example problem for simplicity: - I have a G…
The goal of the tutorial is to teach the user how to use functions in C++. The video will cover how to define functions, how to call functions and how to create functions prototypes. Microsoft Visual C++ 2010 Express will be used as a text editor an…
The viewer will learn how to user default arguments when defining functions. This method of defining functions will be contrasted with the non-default-argument of defining functions.

710 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question