CoolInterview.com - World's Largest Collection of Interview Questions & Answers, FAQs, queries, sample papers, exam papers, dumps, what, why, how, where, when questions
Interview Success Kit - Get Success in Job Interviews Interview Success Kit - 30,000 Interview Que. & Ans.
Covers 30,000+ Interview Questions asked in actual MNC Interviews - all with model answers.
Get Your Dream Job Now - www.vyoms.com
Sponsored Links
Interview Questions
Our Services

INTERVIEW QUESTIONS HARDWARE EMBEDDED SYSTEMS DETAILS
Question :
Can you have constant volatile variable?
Category Embedded Systems Interview Questions
Rating (3.9) By 37 users
Added on 7/6/2010
Views 2312
Rate it!
Answers:



yes we can have constant volatile variable.

In this current context of code will not change the value of the variable but out side of the program i.e. hardware registers can change it.



Posted by: rajkumar

Contact rajkumar Contact rajkumar

In some scenarios expressions having volatile variables cant be optimized by a compiler.



Posted by: shashank vimal

Contact shashank vimal Contact shashank vimal

precisely volatile variable warns the compiler that the value of the variable may change at any time without the knowledge of the compiler, to the code currently executed.
volatile int * const port_add = 0x400;



Posted by: Murali Prasath

Contact Murali Prasath Contact Murali Prasath

Volatile type tell the compiler , this variable can be changed by any external tasks, So do not optimize while compiling and linking final executable.
Here is Example:


In Embedded system System Timer is one of the most important.

func()
{
TIME* time;
time = GetSystime();

for ( 1000 times )
{
some expressions;
}
time = GetSystime();
}

In the above function , time is a structure which gets the time before and after FOR loop.
At these two instances time is definitely different, because of FOR loop. If you go for an embedded system compiler, generally it optimizes the "time = GetSystime();" expression. because it thought that, code is redundant no need to load the getsystime value again from memory , if u dont use VOLATILE. to avoid this kind of things use Volatile.



Posted by: Jay

Contact Jay Contact Jay

If you have the better answer, then send it to us. We will display your answer after the approval.
Rules to Post Answers in CoolInterview.com:-

  • There should not be any Spelling Mistakes.
  • There should not be any Gramatical Errors.
  • Answers must not contain any bad words.
  • Answers should not be the repeat of same answer, already approved.
  • Answer should be complete in itself.
  • Name :*
    Email Id :*
    Answer :*
    Verification Code Code Image - Please contact webmaster if you have problems seeing this image code Not readable? Load New Code
    Process Verification Enter the above shown code: *
    Inform me about updated answers to this question

    Related Questions
    View Answer
    #define cat(x,y) x##y concatenates x to y. But cat(cat(1,2),3) does not expand but gives preprocessor warning. Why?
    View Answer
    What is the output of printf(" abcd ef"); -> ef
    View Answer
    When you inherit a class using private keyword which members of base class are visible to the derived class?
    View Answer
    Can u have inline virtual functions in a class?
    View Answer
    Order of constructor and destructor call in case of multiple inheritance?
    View Answer
    Is java a pure object oriented language? Why?
    View Answer
    How would you find out the no of instance of a class?
    View Answer
    What are the 4 different types of inheritance relationship?
    View Answer
    Multiple inheritance - objects contain howmany multiply inherited ancestor?
    View Answer
    Difference between object oriented and object based languages?
    View Answer
    Scope of static variables?
    View Answer
    What happens when recursion functions are declared inline?
    View Answer
    Advantages and disadvantages of using macro and inline functions?
    View Answer
    Why cannot arrays be passed by values to functions?
    View Answer
    Can structures be passed to the functions by value?
    View Answer

    Please Note: We keep on updating better answers to this site. In case you are looking for Jobs, Pls Click Here Vyoms.com - Best Freshers & Experienced Jobs Website.

    View ALL Embedded Systems Interview Questions & Answers

    User Options
    Latest 20 Questions
    What is cross cutting concern and concern in spring AOP ?
    What are the important beans lifecycle methods ?
    Explain the advantages of using DAO module?
    What is SQLProvider ?
    How struts application can be integrated with spring?
    What are the advantages of spring framework?
    What is ?Throws advice? in Spring ?
    What is Metadata Autoproxying ?
    Describe about DAO in Spring framework ?
    What is called an Advice ?
    What is IOC?
    What are the types of Dependency Injection?
    What are the different Modes of Autowiring ?
    Define Application context module?
    Why Spring framework is needed?
    What is called Spring MVC?
    What is Bean Factory?
    What is the default scope of bean in Spring framework?
    How to create arrays in JavaScript?
    How can JavaScript codes be hidden from old browsers that don?t support JavaScript ?


    Copyright ©2003-2016 CoolInterview.com, All Rights Reserved.
    Privacy Policy | Terms and Conditions

    Download Yahoo Messenger | Placement Papers| FREE SMS | ASP .Net Tutorial | Web Hosting | Dedicated Servers | C Interview Questions & Answers

    Testing Articles | Testing Books | Testing Certifications | Testing FAQs | Testing Downloads | Testing Interview Questions | Testing Jobs | Testing Training Institutes


    Cache = 0.436523 Seconds