Face detection is a computer technology that determines the locations and sizes of human faces in arbitrary (digital) images. It detects facial features and ignores anything else, such as buildings, trees and bodies.

A Ruby library to queue and defer processing of slow methods like sending email and image resizing.

Use for questions about using Android Studio, an official IDE targeted at Android development. Do NOT use for questions about programming for Android in general; instead use [android].

final is a common keyword specifying that the reference declared as final cannot be modified once it is initialized. In Java the keyword final is roughly equivalent to const in C++. In C++ the final keyword allows you to declare a virtual method, override it N times and then mandate that 'this can no longer be overridden'.

C library function for reallocating a dynamically allocated memory region.

A Unix shell command that breaks input into fields, which can be selected for output, based on a delimiter.

A template engine is software that is designed to process templates and content information to produce output documents.

A button that will take the user back to the previous state that they were on.

Rack provides a minimal interface between webservers supporting Ruby and Ruby frameworks.

DO NOT USE THIS TAG. Questions about the history of programming are off-topic. For questions about browser history, use [browser-history] instead. For questions about the JavaScript library, use [history.js]. For questions about the HTML5 API, use [html5-history]. For questions about version control, use [revision-history]. For questions about recalling inputs in an entry box, use [input-history].

An outer join defines a relationship between two tables where all records from one or both tables are returned regardless of the existence of a matching key-field in the other table. A full outer join combines the results of both tables. A left or right join returns all the records from the first or second specified table, respectively. NULLS are filled in for matches on either side. A self-join compares a table to a copy of itself.