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What is the performance cost of having a virtual method in a C++ class?

...3ghz in-order PowerPC processor. On that architecture, a virtual function call costs 7 nanoseconds longer than a direct (non-virtual) function call. So, not really worth worrying about the cost unless the function is something like a trivial Get()/Set() accessor, in which anything other than inli...
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Android Writing Logs to text File

... code of Mine but then this method creates file but contains nothing. Basically I want to read previous contents of the file and then append my data with the existing content. ...
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Reading header data in Ruby on Rails

..."Cookie"] New way: request.headers["HTTP_COOKIE"] To get a Hash with all headers of the request. request.headers share | improve this answer | follow |...
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How to check what version of jQuery is loaded?

... containing the version number. If you get back a version number -- usually as a string -- then jQuery is loaded and that is what version you're working with. If not loaded then you should get back undefined or maybe even an error. Pretty old question and I've seen a few people that have alrea...
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How to determine the encoding of text?

... Correctly detecting the encoding all times is impossible. (From chardet FAQ:) However, some encodings are optimized for specific languages, and languages are not random. Some character sequences pop up all the time, while other sequences make no...
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Static nested class in Java, why?

...ike any other top-level class. In effect, a static nested class is behaviorally a top-level class that has been nested in another top-level class for packaging convenience. There is no need for LinkedList.Entry to be top-level class as it is only used by LinkedList (there are some other interface...
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What is the difference between NTFS Junction Points and Symbolic Links?

...nks is that Junctions are only able to be directories, while SymLinks are allowed to also target files. 6 Answers ...
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What is a “callback” in C and how are they implemented?

...y're implemented using function pointers. Here's an example: void populate_array(int *array, size_t arraySize, int (*getNextValue)(void)) { for (size_t i=0; i<arraySize; i++) array[i] = getNextValue(); } int getNextRandomValue(void) { return rand(); } int main(void) { int m...
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How to set default value for form field in Symfony2?

..., it will also always force the value under any context. Not what I would call a "default value"... – Hubert Perron Apr 3 '13 at 18:25 4 ...
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One or more types required to compile a dynamic expression cannot be found. Are you missing referenc

... The Visual Studio team should really think about letting people mouse over the error and then select "Add Microsoft.CSharp to References" – geoyws May 12 '14 at 7:04 ...