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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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Unresolved specs during Gem::Specification.reset:

...t turned out to be a missing line in the gemspec file: $:.push File.expand_path("../lib", __FILE__) This line is normally at the top of the file (in many of the gems I have recently been working in) and I had commented it out to see why. ...
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Which letter of the English alphabet takes up most pixels?

I am trying to do some dynamic programming based on the number of characters in a sentence. Which letter of the English alphabet takes up the most pixels on the screen? ...
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How to get GET (query string) variables in Express.js on Node.js?

...et the variables in the query string in Node.js just like we get them in $_GET in PHP? 26 Answers ...
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How to test equality of Swift enums with associated values

...problem @MichaelWaterfall mentioned by replacing default with case (.Name, _): return false; case(.Number, _): return false. – Kazmasaurus Aug 5 '15 at 23:30 25 ...
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ASP.NET MVC: Custom Validation by DataAnnotation

...ss UniqueFileName : ValidationAttribute { private readonly NewsService _newsService = new NewsService(); public override bool IsValid(object value) { if (value == null) { return false; } var file = (HttpPostedFile) value; return _newsService.IsFileNameUnique(fi...
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Is a view faster than a simple query?

...t is materialized immediately and persisted in physical storage in the database, saving the overhead of performing this costly operation at execution time. Second, these indexed views can work even when they are not directly referenced by another query as the optimizer will use them in place of a ...
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Session variables in ASP.NET MVC

...art event void OnSessionStart(...) { HttpContext.Current.Session.Add("__MySessionObject", new MySessionObject()); } From anywhere in code where the HttpContext.Current property != null you can retrive that object. I do this with an extension method. public static MySessionObject GetMySession...
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How to get a key in a JavaScript object by its value?

... With the Underscore.js library: var hash = { foo: 1, bar: 2 }; (_.invert(hash))[1]; // => 'foo' share | improve this answer | follow | ...
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Reset Entity-Framework Migrations

...te the state: Delete the migrations folder in your project; And Delete the __MigrationHistory table in your database (may be under system tables); Then Run the following command in the Package Manager Console: Enable-Migrations -EnableAutomaticMigrations -Force Use with or without -EnableAutomati...