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When would anyone use a union? Is it a remnant from the C-only days?

I have learned but don't really get unions. Every C or C++ text I go through introduces them (sometimes in passing), but they tend to give very few practical examples of why or where to use them. When would unions be useful in a modern (or even legacy) case? My only two guesses would be programming ...
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std::function and std::bind: what are they, and when should they be used?

...nd to get g: auto g = bind(f, _1, 4, _2); This is more concise than actually writing a functor class to do it. There are further examples in the article you link to. You generally use it when you need to pass a functor to some algorithm. You have a function or functor that almost does the job yo...
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How do you do a limit query in JPQL or HQL?

...QL Parser, and it's a lot less forgiving. I think Query.setMaxResults() really is your only option. share | improve this answer | follow | ...
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Django: How to completely uninstall a Django app?

What is the procedure for completely uninstalling a Django app, complete with database removal? 5 Answers ...
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Is there a TRY CATCH command in Bash

... writing a shell script and need to check that a terminal app has been installed. I want to use a TRY/CATCH command to do this unless there is a neater way. ...
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Will the base class constructor be automatically called?

... age of customer be 2? It seems like the base class's constructor will be called no matter what. If so, why do we need to call base at the end sometimes? ...
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Determining Referer in PHP

...s the most reliable and secure way to determine what page either sent, or called (via AJAX), the current page. I don't want to use the $_SERVER['HTTP_REFERER'] , because of the (lack of) reliability, and I need the page being called to only come from requests originating on my site. Edit: I am...
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namedtuple and default values for optional keyword arguments

...lds) >>> Node() Node(val=None, left=None, right=None) Order In all versions of Python, if you set fewer default values than exist in the namedtuple, the defaults are applied to the rightmost parameters. This allows you to keep some arguments as required arguments. >>> Node.__ne...
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How do I find where an exception was thrown in C++?

I have a program that throws an uncaught exception somewhere. All I get is a report of an exception being thrown, and no information as to where it was thrown. It seems illogical for a program compiled to contain debug symbols not to notify me of where in my code an exception was generated. ...
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Determine distance from the top of a div to top of window with javascript

... variable to see if it's value is 120 but I would recommend checking for a range instead of an exact number. If for instance you scroll with a mouse-wheel, you might very well skip over 120. So if you are trying to apply some CSS or something when the element is within 120px of the top-fold, then ma...