volatile keyword in C++

I came across the keyword volatile for the first time.

It is used to prevent the compiler from modifying a segment of code for optimization. Variables defined with volatile keyword can be used for:

• accessing memory mapped devices
• signal handlers etc.

Here is an example (from wikipedia).

static int foo;
 
void bar(void) {
    foo = 0;
 
    while (foo != 255)
         ;
}

This code will be optimized to:

void bar_optimized(void) {
    foo = 0;
 
    while (true)
         ;
}

by an optimizing compiler.

If, however, the variable foo can change outside the code, we do not want the compiler to modify it. So, we use the volatile keyword as follows:

static volatile int foo;
 
void bar (void) {
    foo = 0;
 
    while (foo != 255)
        ;
}

SVN Checkout

SVN stands for subversion.It is a version control software that allows users to download latest version of a particular branch without having to wait until it is properly packaged and delivered.

Here is how you can checkout from svn.

svn checkout <here you enter the web page address>

How to change font size in LaTex equations

Credit should go to original contributor. I am just sharing here.

\documentclass{article} \usepackage{amsmath}
 \begin{document}

 \begin{eqnarray} 2x+3 \end{eqnarray}

 \makeatletter
 \def\@eqnnum{{\normalsize \normalcolor (\theequation)}}
  \makeatother
 { \small \begin{eqnarray} 2x+3 \end{eqnarray} }
 \end{document} 



to make sure the size of the equation numbers are not changed we have included a redefinition of the eqnnum command.
\makeatletter  \def\@eqnnum{{\normalsize \normalcolor (\theequation)}}  
\makeatother

available sizes:

• \tiny
• \scriptsize
• \footnotesize
• \small
• \normalsize (default)
• \large
• \Large (capital "L")
• \LARGE (all caps)
• \huge
• \Huge (capital "H")