It&#39;s _MSC_VER. More info [at MSDN][1] and [at predef][2].

But, be aware that some other compilers may also define it, e.g. Intel&#39;s C++ Compiler for Windows also defines _MSC_VER. If this is a concern, use `#if _MSC_VER &amp;&amp; !__INTEL_COMPILER`.


  [1]: http://msdn.microsoft.com/en-us/library/b0084kay.aspx
  [2]: http://sourceforge.net/p/predef/wiki/Compilers/#microsoft-visual-c

Look at the list of [MSVC predefined macros](https://docs.microsoft.com/en-us/cpp/preprocessor/predefined-macros). You&#39;ll find what you need.

`_MSC_VER` is probably a good one.

_MSC_VER is one such [predefined macro][1].


  [1]: http://msdn.microsoft.com/en-us/library/b0084kay%28v=vs.80%29.aspx

Okay, its a very lame question for many but I hope I will have overwhelming response :)

When I throw an Exception in PHP I can add a code to the message.&lt;br&gt;
I catch an exception and handle it according to its type (Like `InvalidArgumentException` or `OutOfBoundException`). I log the &lt;strong&gt;message&lt;/strong&gt; or display it or do whatever is suitable.&lt;br&gt; 
I can add also append a previous exception to trace a path to the origin of the error.&lt;br&gt;

BUT one thing I have never used or never thought of: how useful is &lt;strong&gt;code&lt;/strong&gt;?&lt;br&gt;

For example: &lt;br&gt;

    throw new Exception(&quot;db Error&quot;, $code, $previousException);


What do I do with `$code`?

What do we need the PHP-exception code for? Any use case scenario?

Event-driven and asynchronous are often used as synonyms. Are there any differences between the two?

Also, what is the difference between `epoll` and `aio`? How do they fit together?

Lastly, I&#39;ve read many times that AIO in Linux is horribly broken. How exactly is it broken?

Thanks.

What&#39;s the difference between event-driven and asynchronous? Between epoll and AIO?

So I can do something like

    #ifdef MSVC
    //do compiler specific code here
    #endif

Is there a preprocessor define that is defined if the compiler is MSVC?

So I can do something like
<pre><code class="hljs language-arduino">#ifdef MSVC
//do compiler specific code here
#endif
</code></pre>

Is there is any difference between using a `std::tuple` and a data-only `struct`?

    typedef std::tuple&lt;int, double, bool&gt; foo_t;

    struct bar_t {
        int id;
        double value;
        bool dirty;
    }

From what I have found online, I found that there are two major differences: the `struct` is more readable, while the `tuple` has many generic functions that can be used.
Should there be any significant performance difference?
Also, is the data layout compatible with each other (interchangeably casted)?

C++ Tuple vs Struct

I know that you can use `const_cast` to cast a `const` to a non-`const`.

But what should you use if you want to cast non-`const` to `const`?

casting non const to const in c++

AFAIK:

C++ provides three different types of polymorphism.

   * Virtual functions
   * Function name overloading
   * Operator overloading

In addition to the above three types of polymorphism, there exist other kinds of polymorphism:

   * run-time
   * compile-time
   * ad-hoc polymorphism
   * parametric polymorphism

I know that _runtime polymorphism_ can be achieved by _virtual functions_
and _static polymorphism_ can be achieved by _template functions_

But for the other two 

   * ad-hoc polymorphism
   * parametric polymorphism
the [website says][1],

**ad-hoc polymorphism:**

If the range of actual types that can be used is finite and the combinations must be individually specified prior to use, this is called ad-hoc polymorphism.

**parametric polymorphism:**

If all code is written without mention of any specific type and thus can be used transparently with any number of new types it is called parametric polymorphism. 

I can hardly understand them :(

can anyone explain them both if possible with an example?
I hope the answers to this questions would be helpful for many new passouts from their colleges.


  [1]: http://www.exforsys.com/tutorials/c-plus-plus/polymorphism-an-introduction.html

Polymorphism in C++

If `s` is a `std::string`, then is there a function like the following?

    s.replace(&quot;text to replace&quot;, &quot;new text&quot;);

How to find and replace string?

&gt; **Possible Duplicate:**  
&gt; [How to split a string in C++?](https://stackoverflow.com/questions/236129/how-to-split-a-string-in-c)  

&lt;!-- End of automatically inserted text --&gt;

I need to split a string by single spaces and store it into an array of strings. I can achieve this using a istringstream, but what I am not being able to achieve is this:

I want every space to terminate the current word. So, if there are two spaces consecutively, one element of my array should be blank.

For example:

(underscore denotes space)

    This_is_a_string.
    gets split into:
    A[0] = This
    A[1] = is
    A[2] = a
    A[3] = string.
    
    This__is_a_string.
    gets split into:
    A[0] = This
    A[1] = &quot;&quot;
    A[2] = is
    A[3] = a
    A[4] = string.

How can I implement this?


Split string by single spaces

This is pasted from a website, which presumably was working. I did some googling and found that the issue I have now is a result of Visual C++ 2010 SP1, which I downloaded today, and is now giving me this error:

`PCH Warning: header stop cannot be in a macro or #if block.`

Hopefully someone will be able to help me with this!

    #ifndef APP_STATE_H
    #define APP_STATE_H
    
    #include &quot;Framework.h&quot;
    
    class AppState; //this line is giving me the error
    
    //define two classes
    
    #endif

Framework.h:

    #ifndef OGRE_FRAMEWORK_H
    #define OGRE_FRAMEWORK_H
    
    #include &lt;OgreCamera.h&gt;
    #include &lt;OgreEntity.h&gt;
    #include &lt;OgreLogManager.h&gt;
    #include &lt;OgreOverlay.h&gt;
    #include &lt;OgreOverlayElement.h&gt;
    #include &lt;OgreOverlayManager.h&gt;
    #include &lt;OgreRoot.h&gt;
    #include &lt;OgreViewport.h&gt;
    #include &lt;OgreSceneManager.h&gt;
    #include &lt;OgreRenderWindow.h&gt;
    #include &lt;OgreConfigFile.h&gt;
    
    #include &lt;OISEvents.h&gt;
    #include &lt;OISInputManager.h&gt;
    #include &lt;OISKeyboard.h&gt;
    #include &lt;OISMouse.h&gt;
    
    class OgreFramework : public Ogre::Singleton&lt;OgreFramework&gt;,OIS::KeyListener,OIS::MouseListener{
    public:
    	OgreFramework();
    	~OgreFramework();
    
    	bool initOgre(Ogre::String wndTitle, OIS::KeyListener *pKeyListener = 0, OIS::MouseListener *pMouseListener = 0);
    	void updateOgre(double timeSinceLastFrame);
    	
    	//OIS
    	bool keyPressed(const OIS::KeyEvent &amp;keyEventRef);
    	bool keyReleased(const OIS::KeyEvent &amp;keyEventRef);
    	bool mouseMoved(const OIS::MouseEvent &amp;evt);
    	bool mousePressed(const OIS::MouseEvent &amp;evt, OIS::MouseButtonID id);
    	bool mouseReleased(const OIS::MouseEvent &amp;evt, OIS::MouseButtonID id);
    
    	Ogre::Root* mRoot;
    	Ogre::RenderWindow* mRenderWnd;
    	Ogre::Viewport* mViewport;
    	Ogre::Log* mLog;
    	Ogre::Timer* mTimer;
    
    	//OIS
    	OIS::InputManager* mInputMgr;
    	OIS::Keyboard* mKeyboard;
    	OIS::Mouse* mMouse;
    private:
    	OgreFramework(const OgreFramework&amp;);
    	OgreFramework&amp; operator= (const OgreFramework&amp;);
    };
    
    #endif

PCH Warning: header stop cannot be in a macro or #if block - Visual C++ 2010 Express SP1 

Is there any tool that can directly test if a library is made for 32 or 64 bit?

Have a static lib, is there a simple way to know it is for 32 bit or 64 bit?

How can I get VS 2010 to run more than one C++ compile process at a time? I mean building object modules in parallel; I&#39;m not interested in building more than one project at a time (I know about Tools &gt; Options &gt; Build and Run &lt; Maximum number of parallel project builds, but that doesn&#39;t do what I want).

Basically, I&#39;m looking for Visual Studio&#39;s equivalent of &quot;make -jN&quot;.

How can I do a parallel build in Visual Studio 2010?

I&#39;ve added several directories, libraries such as matlab, opencv, etc to compile my current C file in Visual Studio project.

All my upcoming projects will require the same setup/properties. Do I need to setup my each project&#39;s properties individually or I can do something to apply it to all ?

Visual Studio: can I copy a project&#39;s properties to use in another project?

While I am running the simple code as below I have two errors as following:

    #include &lt;iostream&gt;
    #include &lt;string&gt;
    using namespace::std;

    template &lt;class Type&gt;
    class Stack
    {
    public:
        Stack (int max):stack(new Type[max]), top(-1), maxsize(max){}
        ~Stack (void) {delete []stack;}
        void Push (Type &amp;val);
        void Pop (void) {if (top&gt;=0) --top;}
        Type&amp; Top (void) {return stack[top];}
        //friend ostream&amp; operator&lt;&lt; (ostream&amp;, Stack&amp;);
    private:
        Type *stack;
        int top;
        const int maxSize;
    };

    template &lt;class Type&gt;
    void Stack &lt;Type&gt;:: Push (Type &amp;val)
    {
        if (top+1&lt;maxsize)
            stack [++top]=val;
    }


Errors:
&gt;MSVCRTD.lib(crtexew.obj) : error LNK2019: unresolved external symbol `_WinMain@16` referenced in function `___tmainCRTStartup`  

What Should I do?

error LNK2019: unresolved external symbol _WinMain@16 referenced in function ___tmainCRTStartup

If there&#39;s some cross-platform C/C++ code that should be compiled on Mac OS X, iOS, Linux, Windows, how can I detect them reliably during preprocessor process?

How to detect reliably Mac OS X, iOS, Linux, Windows in C preprocessor?

What is the point of `#define` in C++? I&#39;ve only seen examples where it&#39;s used in place of a &quot;magic number&quot; but I don&#39;t see the point in just giving that value to a variable instead.

Why use #define instead of a variable

It&#39;s simple question but why would someone use #define to define constants?

What&#39;s the difference between

`#define sum 1` and `const int sum = 1;`


Why would someone use #define to define constants?

&gt; **Possible Duplicates:**  
&gt; [Why would someone use #define to define constants?](https://stackoverflow.com/questions/6274008/why-would-someone-use-define-to-define-constants)  
&gt; [difference between a macro and a const in c++](https://stackoverflow.com/questions/6393776/difference-between-a-macro-and-a-const-in-c)  
&gt; [C++ - enum vs. const vs. #define](https://stackoverflow.com/questions/4767667/c-enum-vs-const-vs-define)  

&lt;!-- End of automatically inserted text --&gt;

What is the difference between using `#define` and `const` for creating a constant? Does any have a performance advantage over the other? Naturally I prefer using the `const` but I&#39;m going to consider the `#define` if it has suitable advantages.    


What is the difference between #define and const?

I just learned of [X-Macros][1]. What real-world uses of X-Macros have you seen? When are they the right tool for the job?


  [1]: http://en.wikibooks.org/wiki/C_Programming/Preprocessor#X-Macros

Content Type	Original Author	Original Content on Stackoverflow
Question	Avery3R	View Question on Stackoverflow
Solution 1 - C++	Alexey Kukanov	View Answer on Stackoverflow
Solution 2 - C++	Mat	View Answer on Stackoverflow
Solution 3 - C++	mbx	View Answer on Stackoverflow
Solution 4 - C++	Will A	View Answer on Stackoverflow

Is there a preprocessor define that is defined if the compiler is MSVC?

C++ Problem Overview

C++ Solutions

Solution 1 - C++

Solution 2 - C++

Solution 3 - C++

Solution 4 - C++

What's the difference between event-driven and asynchronous? Between epoll and AIO?

What do we need the PHP-exception code for? Any use case scenario?

Attributions