**Code**

The text of a `QLabel` can be made selectable by mouse like so:

    label-&gt;setTextInteractionFlags(Qt::TextSelectableByMouse);

This is found in the [QLabel documentation][2].

You can use that same function to make links selectable by keyboard, highlight URL links, and make the text editable. See [Qt::TextInteractionFlag][1].

**Designer**

Search for `textInteractionFlags` under the `QLabel` menu and set the flag `TextSelectableByMouse`.

  [1]: http://qt-project.org/doc/qt-5.0/qtcore/qt.html#TextInteractionFlag-enum
  [2]: http://qt-project.org/doc/qt-5.0/qtwidgets/qlabel.html#textInteractionFlags-prop

Here is another method, for reference...
You could create a QLineEdit subclass instead, tweaked to look and act like a QLabel,
in the constructor:

     setReadOnly(true);
     setFrame(false);
     QPalette palette = this-&gt;palette();
     palette.setColor(QPalette::Base, palette.color(QPalette::Background));
     setPalette(palette);
I think the accepted answer is simpler and preferable to this though.

How to pass dictionary as command line argument to Python script?
I need to get dictionary where key is string and value is list of some elements 
– for example to look like:

    command_line_arguments = {&quot;names&quot; : [&quot;J.J.&quot;, &quot;April&quot;], &quot;years&quot; : [25, 29]}

I have tried like 

    if __name__ == &#39;__main__&#39;:
        args = dict([arg.split(&#39;=&#39;) for arg in sys.argv[2:]]) # also tried with 1 but doesn&#39;t work
        main(args)

and I am calling script like 

    $ python saver.py names=[&quot;J.J.&quot;, &quot;April&quot;] years=[25, 29]

but it doesn&#39;t work, dictionary has length 0 and need 2. Can anyone help me to pass and create dictionary in main.

How to pass dictionary as command line argument to Python script?

Consider following code:

    #include &lt;iostream&gt;
    #include &lt;type_traits&gt;
    
    template &lt;typename T&gt;
    struct A {
        int val = 0;
    
        template &lt;class = typename std::enable_if&lt;T::value&gt;::type&gt;
        A(int n) : val(n) {};
        A(...) { }

        /* ... */
    };
    
    struct YES { constexpr static bool value = true; };
    struct NO { constexpr static bool value = false; };
    
    int main() {
        A&lt;YES&gt; y(10);
        A&lt;NO&gt; n;
        std::cout &lt;&lt; &quot;YES: &quot; &lt;&lt; y.val &lt;&lt; std::endl
                  &lt;&lt; &quot;NO:  &quot; &lt;&lt; n.val &lt;&lt; std::endl;
    }

I want to selectively define constructor A::A(int) only for some types using enable_if. For all other types there is default constructor A::A(...) which should be the default case for compiler when substitution fails. However this makes sense for me compiler (gcc version 4.9.0 20130714) is still complaining 

&gt; sfinae.cpp: In instantiation of &#39;struct A&lt;NO&gt;&#39;: sfinae.cpp:19:11:  
&gt; required from here sfinae.cpp:9:5: error: no type named &#39;type&#39; in  
&gt; &#39;struct std::enable_if&lt;false, void&gt;&#39;  
&gt;      A(int n) : val(n) {};  

Is something like this possible for constructor? Is this possible with another constructor(s) (copy-constructor and move-constructor)?

Select class constructor using enable_if

I have a `QLabel` in my application that displays error messages to the user. I would like to make the text of the label selectable so users can copy and paste the error message if needed.

However, when I use the mouse to click and drag over the text, nothing happens - the text is not selected.

How can I make the text within a `QLabel` selectable by the mouse?

Make QLabel text selectable?

I have a <code>QLabel</code> in my application that displays error messages to the user. I would like to make the text of the label selectable so users can copy and paste the error message if needed.
However, when I use the mouse to click and drag over the text, nothing happens - the text is not selected.
How can I make the text within a <code>QLabel</code> selectable by the mouse?

Given all three functions, this call is ambiguous.

    int f( int );
    int f( int &amp;&amp; );
    int f( int const &amp; );
    
    int q = f( 3 );

Removing `f( int )` causes both Clang and GCC to prefer the rvalue reference over the lvalue reference. But instead removing either reference overload results in ambiguity with `f( int )`.

Overload resolution is usually done in terms of a strict partial ordering, but `int` seems to be equivalent to two things which are not equivalent to each other. What are the rules here? I seem to recall a defect report about this.

Is there any chance `int &amp;&amp;` may be preferred over `int` in a future standard? The reference must bind to an initializer, whereas the object type is not so constrained. So overloading between `T` and `T &amp;&amp;` could effectively mean &quot;use the existing object if I&#39;ve been given ownership, otherwise make a copy.&quot; (This is similar to pure pass-by-value, but saves the overhead of moving.) As these compilers currently work, this must be done by overloading `T const &amp;` and `T &amp;&amp;`, and explicitly copying. But I&#39;m not even sure even that is strictly standard.

Overload resolution between object, rvalue reference, const reference

I&#39;m trying to explore all the options of the new C++11 standard in depth, while using std::async and reading its definition, I noticed 2 things, at least under linux with gcc 4.8.1 :

 - it&#39;s called *async*, but it got a really &quot;sequential behaviour&quot;, basically in the row where you call the *future* associated with your async function *foo*, the program blocks until the execution of *foo* it&#39;s completed. 
 - it depends on the exact same external library as others, and better, non-blocking solutions, which means `pthread`, if you want to use `std::async` you need pthread.

at this point it&#39;s natural for me asking why choosing std::async over even a simple set of functors ? It&#39;s a solution that doesn&#39;t even scale at all, the more future you call, the less responsive your program will be.

Am I missing something ? Can you show an example that is granted to be executed in an async, non blocking, way ?

Why should I use std::async?

I know this is pretty common question, but still new for me!

I don&#39;t understand concept of dangling pointer, was googling around, and writing test methods to find one.

I just wonder is this a dangling pointer? As whatever example I found was returning something, here I&#39;m trying something similar!

Thanks!
  
&lt;!-- language: lang-cxx --&gt;

    void foo(const std::string name)
    {
        // will it be Dangling pointer?!, with comments/Answer
        // it could be if in new_foo, I store name into Global.
        // Why?! And what is safe then?
        new_foo(name.c_str());
    }
    
    void new_foo(const char* name)
    {
        // print name or do something with name...   
    }


What is a dangling pointer?

Question is simple, how would I implement a function taking a variable number of arguments (alike the variadic template), however where all arguments have the same type, say int.

I was thinking about something alike this;

    void func(int... Arguments)

Alternatively wont a recursive static assert on the types work?

C++11 variable number of arguments, same specific type

I am not a C programmer, so I am not that familiar with C-string but now I have to use a C library so here is a shortened version of my code to demonstrate my problem: 

    char** ReadLineImpl::my_completion () {
        char* matches[1];
        matches[0] = &quot;add&quot;;
    
        return matches;
    }

I am getting this warning:

&gt;Warning - address of stack memory associated with local variable &#39;matches&#39; returned

And my program does not seem to work properly (might be because of the above mentioned warning).

What does the warning imply? and will it cause any problems?


Using C-string gives Warning: &quot;Address of stack memory associated with local variable returned&quot;

I just reinstalled QtCreator, created new project (*Qt Application*) an got this after compilation: 

    /usr/bin/ld: **cannot find -lGL**
    collect2: error: ld returned 1 exit status
    make: *** [untitled1] Error 1
    18:07:41: The process &quot;/usr/bin/make&quot; exited with code 2.
    Error while building/deploying project untitled1 (kit: Desktop Qt 5.1.0 GCC 32bit)
    When executing step &#39;Make&#39;

(*Project is empty, I did&#39;n commit any changes*)

&gt; Qt Creator 2.7.2  
Based on Qt 5.1.0 (32 bit)  
Ubuntu 13.04

How do I solve this problem?

Qt: can&#39;t find -lGL error

I am porting code from qt4 to qt5. I added the following line to my `.pro` file, [as suggested][1]:
  
    QT += webkitwidgets

However, when I run `qmake`, I get the this error:

    Project ERROR: Unknown module(s) in QT: webkitwidgets

I am developing on Ubuntu 12.04 LTS and installed Qt [as described][2].


  [1]: http://qt-project.org/wiki/Transition_from_Qt_4.x_to_Qt5
  [2]: https://askubuntu.com/questions/279421/how-can-i-install-qt-5-x-on-12-04-lts

Project ERROR: Unknown module(s) in QT: webkitwidgets

I want to code a notification window at the bottom right corner of the desktop, so it works like Skype notifications when someone comes online. Can someone help me get the screen size of the desktop, so I can place my notification window at the bottom right corner using my Qt Application?

How can I find the screen/desktop size in Qt, so I can display a desktop notification?

I&#39;m developing a program in Qt. Its makefile is generated automatically from the .pro file. I need to use some code which need the -std=c++11 flag to be set up for g++. Where in .pro should I add this flag? (changing only the Makefile won&#39;t work since it gets overwritten by the newly generated one, each time I build the project).

C++ Qt - How to add &quot;-std=c++11&quot; to the makefile which is generated by qmake?

Which C++ compiler currently has *complete* C++11 support on windows platform? 

Microsoft compiler currently does not have full C++11 support (and it won&#39;t be added any time soon).  
MinGW g++ (from mingw.org) does not support `std::thread` out of the box. It also can&#39;t compile Qt 4 sources (runs out of memory while building QtGuid4.dll, known workarounds didn&#39;t work for me).  
I&#39;ve wasted several days trying to make clang work on windows, managed to compile it, but couldn&#39;t enable c++11 support because it required libstdc++ which (I think) wasn&#39;t ported to windows platform at that moment. It also isn&#39;t supported by Qt 4.

What else is there? I&#39;ve been working for C++03 for a long time, and I&#39;d like to give new features a whirl, but I don&#39;t really want a tool that with incomplete support (that&#39;ll add extra headache while writing a code) or can run out of memory  (on 8GB system) while linking a library.

I&#39;m working on windows 7 64bit, and although having 64bit support would be nice, I&#39;m mostly interested in 32bit applications, so ability to produce 64bit executables is optional.

Any suggestions?

Content Type	Original Author	Original Content on Stackoverflow
Question	Cory Klein	View Question on Stackoverflow
Solution 1 - C++	Cory Klein	View Answer on Stackoverflow
Solution 2 - C++	Don Hatch	View Answer on Stackoverflow

Make QLabel text selectable?

C++ Problem Overview

C++ Solutions

Solution 1 - C++

Solution 2 - C++

Select class constructor using enable_if

How to pass dictionary as command line argument to Python script?

Attributions