It&#39;s called an unnamed namespace / anonymous namespace. It&#39;s use is to make functions/objects/etc accessible only within that file. It&#39;s almost the same as `static` in C.

A mac newbie question: I have an older version of Xcode and want to update it to a newer version. How do I do that?

How to update Xcode?

I&#39;m making an ajax call using jquery to an asp.net mvc controller action:

    [AcceptVerbs(HttpVerbs.Post)]
            public ActionResult GetWeek(string startDay)
            {
                var daysOfWeek = CompanyUtility.GetWeek(User.Company.Id, startDay);
                return Json(daysOfWeek);
            }

When session times out, this call will fail, as the User object is stored in session. I created a custom authorize attribute in order to check if session was lost and redirect to the login page. This works fine for page requests, however it doesn&#39;t work for ajax requests, as you can&#39;t redirect from an ajax request:

    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Method)]
        public class AuthorizeUserAttribute : AuthorizeAttribute
        {
            protected override bool AuthorizeCore(HttpContextBase httpContext)
            {
                if (!httpContext.Request.IsAjaxRequest())
                {//validate http request.
                    if (!httpContext.Request.IsAuthenticated
                        || httpContext.Session[&quot;User&quot;] == null)
                    {
                        FormsAuthentication.SignOut();
                        httpContext.Response.Redirect(&quot;~/?returnurl=&quot; + httpContext.Request.Url.ToString());
                        return false;
                    }
                }
                return true;
            }
        }

I read on another thread that when the user isn&#39;t authenticated and you make an ajax request, you should set the status code to 401 (unauthorized) and then check for that in js and redirect them to the login page. However, I can&#39;t get this working:

    protected override void OnActionExecuting(ActionExecutingContext filterContext)
            {
                if (Request.IsAjaxRequest() &amp;&amp; (!Request.IsAuthenticated || User == null))
                {
                    filterContext.RequestContext.HttpContext.Response.StatusCode = 401;
                }
                else
                {
                    base.OnActionExecuting(filterContext);
                }
            }

Basically, it&#39;ll set it to 401, but then it&#39;ll continue into the controller action and throw an object ref not set to an instance of an object error, which then returns error 500 back to the client-side js. If I change my custom Authorize attribute to validate ajax requests as well and return false for those that aren&#39;t authenticated, that makes the ajax request return my login page, which obviously doesn&#39;t work.

How do I get this working?

Handling session timeout in ajax calls

&gt; **Possible Duplicate:**  
&gt; [Unnamed/anonymous namespaces vs. static functions](https://stackoverflow.com/questions/154469/unnamed-anonymous-namespaces-vs-static-functions)  

&lt;!-- End of automatically inserted text --&gt;

I came across this code 

    namespace ABC {
    namespace DEF {
    
    namespace
    {

I expected the namespace should be followed by some name, but it&#39;s not the case with this code.

Is this allowed in C++? What&#39;s the advantage for this unnamed namespace? 

Namespace without a name in C++

> Possible Duplicate: 
> <a href="https://stackoverflow.com/questions/154469/unnamed-anonymous-namespaces-vs-static-functions" target="_blank" rel="noopener noreferrer">Unnamed/anonymous namespaces vs. static functions</a>

I came across this code
<pre><code class="hljs language-arduino">namespace ABC {
namespace DEF {

namespace
{
</code></pre>
I expected the namespace should be followed by some name, but it's not the case with this code.
Is this allowed in C++? What's the advantage for this unnamed namespace?

GNU gdb Fedora (6.8-37.el5)
    Kernal 2.6.18-164.el5

I am trying to debug my application. However, everytime I pass the binary to the gdb it says:

    (no debugging symbols found)

Here is the file output of the binary, and as you can see it is not stripped:

    vid: ELF 32-bit LSB executable, Intel 80386, version 1 (SYSV), for GNU/Linux 2.6.9, dynamically linked (uses shared libs), for GNU/Linux 2.6.9, not stripped

I am compiling with the following CFLAGS:

    CFLAGS = -Wall -Wextra -ggdb -O0 -Wunreachable-code

Can anyone tell me if I am missing some simple here?

no debugging symbols found when using gdb

In C++11, should the operation of static_assert within a template depend on whether that template has been instantiated or not? For example, with the following code 

    template &lt;int I&gt;
    void sa() { static_assert(0,&quot;Hello.&quot;); }
    
    int main(int argc, char *argv[]) { return 0; }

GCC 4.5.0 will fail the assertion, and produce the &quot;Hello.&quot; message.
The Digital Mars Compiler version 8.42n on the other hand, gives no message.


C++11 static_assert and template instantiation

This question may be naive, but:

 - is there `const` keyword in C?
 - since which version?
 - are there any semantic and/or syntactic differences between `const` in C and C++?    




Is there const in C?

What if I write return statement in constructor? Is it standard conformant?

    struct A
    { 
         A() { return; } 
    };

The above code compiles fine, without any error at [ideone][1]. But the following code doesn&#39;t:

    struct A
    { 
       A() { return 100; } 
    };

It gives this error at [ideone][2]:

&gt;error: returning a value from a constructor

I understand that returning value from constructor doesn&#39;t make sense at all, because it doesn&#39;t *explicitly* mention return type, and we cannot store the returned value after all. But I&#39;m curious to know :

- Which statement from the C++ Standard allows the first example  but forbids the second one? Is there any *explicit* statement?
- Is the return *type* in the first example `void`? 
- Is there any *implicit* return type at all?

[1]:http://www.ideone.com/fmpsg
[2]:http://www.ideone.com/50kxf



What if I write return statement in constructor?

    #define STR1      &quot;s&quot;
    #define STR2      &quot;1&quot;
    #define STR3      STR1 ## STR2

Is it possible to concatenate `STR1` and `STR2`, to `&quot;s1&quot;`?
You can do this by passing args to another Macro function. But is there a direct way?


C/C++ macro string concatenation

Can PHP namespaces contain variables? If so, how can this be accomplished?

Can PHP namespaces contain variables?

When would one use unnamed namespace in C++ ? Is it better in any sense than a free standing function? Also, should it be used only in source file and not in header file?

Uses of unnamed namespace in C++

when I write Python code from the interpreter I can type `dir()` to have a list of names defined in the current scope. How can achieve to have the same information, programmatically, when I develop Javascript code from a browser using an interactive console like firebug, chrome console, etc?


Equivalent of Python&#39;s dir in Javascript

I&#39;m working with VS2010 express on Win7 (64 bit) and I&#39;m trying use `System.ServiceModel` but I get an error that there is no `ServiceModel` in the `System` namespace:

&gt; The type or namespace name &#39;ServiceModel&#39; does not exist in the namespace &#39;System&#39; (are you missing an assembly reference?)

I looked in `\Windows\Microsoft.NET\Framework\v4.0.30319` and there are some `ServiceModel___.dll` files but I don&#39;t know if I&#39;m missing something or if they are corrupted.

Any advice?

Thanks,
Yonatan

System.ServiceModel missing

In all our c++ courses, all the teachers always put `using namespace std;` right after the `#include`s in their `.h` files. This seems to me to be dangerous since then by including that header in another program I will get the namespace imported into my program, maybe without realizing, intending or wanting it (header inclusion can be very deeply nested).

So my question is double: Am I right that `using namespace` should not be used in header files, and/or is there some way to undo it, something like:

    //header.h
    using namespace std {
    .
    .
    .
    }

One more question along the same lines: Should a header file `#include` all the headers that it&#39;s corresponding `.cpp` file needs, only those that are needed for the header definitions and let the `.cpp` file `#include` the rest, or none and declare everything it needs as `extern`?  
The reasoning behind the question is the same as above: I don&#39;t want surprises when including `.h` files.

Also, if I am right, is this a common mistake? I mean in real-world programming and in &quot;real&quot; projects out there.

Thank you.

Content Type	Original Author	Original Content on Stackoverflow
Question	prosseek	View Question on Stackoverflow
Solution 1 - C++	Marlon	View Answer on Stackoverflow

Namespace without a name in C++

C++ Problem Overview

C++ Solutions

Solution 1 - C++

Handling session timeout in ajax calls

How to update Xcode?

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