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Why are #ifndef and #define used in C++ header files?
...his case HEADERFILE_H) is defined. Then if it's not defined, it defines it and continues to the rest of the page.
When the code is included again, the first ifndef fails, resulting in a blank file.
That prevents double declaration of any identifiers such as types, enums and static variables.
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Why is it not possible to extend annotations in Java?
I don't understand why there is no inheritance in Java annotations, just as Java classes. I think it would be very useful.
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How can I add reflection to a C++ application?
... to be able to introspect a C++ class for its name, contents (i.e. members and their types) etc. I'm talking native C++ here, not managed C++, which has reflection. I realise C++ supplies some limited information using RTTI. Which additional libraries (or other techniques) could supply this informat...
Checking if an Android application is running in the background
... completely reliable:
The right solution (credits go to Dan, CommonsWare and NeTeInStEiN)
Track visibility of your application by yourself using Activity.onPause, Activity.onResume methods. Store "visibility" status in some other class. Good choices are your own implementation of the Application o...
MySQL: Large VARCHAR vs. TEXT?
... in MySQL which records messages between users. Apart from the typical ids and message types (all integer types) I need to save the actual message text as either VARCHAR or TEXT. I'm setting a front-end limit of 3000 characters which means the messages would never be inserted into the db as longer t...
what’s the difference between Expires and Cache-Control headers?
What’s the difference between Expires and Cache-Control headers?
7 Answers
7
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Why does this loop produce “warning: iteration 3u invokes undefined behavior” and output more than 4
...s no such thing as "unsigned integer overflow") means undefined behaviour. And this means anything can happen, and discussing why does it happen under the rules of C++ doesn't make sense.
C++11 draft N3337: §5.4:1
If during the evaluation of an expression, the result is not mathematically de...
About Java cloneable
...torials explaining about Java Cloneable , but did not get any good links, and Stack Overflow is becoming more obvious choice anyways.
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What is the “continue” keyword and how does it work in Java?
I saw this keyword for the first time and I was wondering if someone could explain to me what it does.
13 Answers
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Unusual shape of a textarea?
...tenteditable
As proposed by @Getz, you can use a div with contenteditable and then shape it with some div on it. Here is an example, with two blocks which float at the upper left and the upper right of the main div:
As you can see, you have to play a little with the borders if you want the same ...