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CoreFoundation
Core Foundation (also called CF) is a C application programming interface (API) written by Apple Inc. for its operating systems, and is a mix of low-level routines and wrapper functions. Most Core Foundation routines follow a certain naming convention that deal with opaque objects, for example CFDictionaryRef for functions whose names begin with CFDictionary, and these objects are often reference counted (manually) through CFRetain and CFRelease. Internally, Core Foundation forms the base of the types in the Objective-C standard library and the Carbon API. The most prevalent use of Core Foundation is for passing its own primitive types for data, including raw bytes, Unicode strings, numbers, calendar dates, and UUIDs, as well as collections such as arrays, sets, and dictionaries, to numerous macOS C routines, primarily those that are GUI-related. At the operating system level Core Foundation also provides standardized application preferences management through CFPropertyLis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Set (computer Science)
In computer science, a set is an abstract data type that can store unique values, without any particular sequence, order. It is a computer implementation of the mathematics, mathematical concept of a finite set. Unlike most other collection (abstract data type), collection types, rather than retrieving a specific element from a set, one typically tests a value for membership in a set. Some set data structures are designed for static or frozen sets that do not change after they are constructed. Static sets allow only query operations on their elements — such as checking whether a given value is in the set, or enumerating the values in some arbitrary order. Other variants, called dynamic or mutable sets, allow also the insertion and deletion of elements from the set. A multiset is a special kind of set in which an element can appear multiple times in the set. Type theory In type theory, sets are generally identified with their indicator function (characteristic function): accord ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bundle (macOS)
In NeXTSTEP, OPENSTEP, and their lineal descendants macOS, iOS, iPadOS, tvOS, watchOS, and visionOS, and in GNUstep, a bundle is a file directory with a defined structure and file extension, allowing related files to be grouped together as a conceptually single item. Examples of bundles that contain executable code include applications, frameworks, and plugins. This kind of bundle usually contains one file representing executable code, and files that represent resources such as nibs, templates, images, sounds, and other media. On some other systems, such as Microsoft Windows, these resources are usually included directly in the executable file itself at compile time. On older Macintoshes, a similar technique is used, where additional metadata can be added to a file's resource fork. Similar in concept are the application directories used in RISC OS and on the ROX Desktop. Examples of bundles that do not contain executable code include document packages (iWork documents) and me ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Endianness
file:Gullivers_travels.jpg, ''Gulliver's Travels'' by Jonathan Swift, the novel from which the term was coined In computing, endianness is the order in which bytes within a word (data type), word of digital data are transmitted over a data communication medium or Memory_address, addressed (by rising addresses) in computer memory, counting only byte Bit_numbering#Bit significance and indexing, significance compared to earliness. Endianness is primarily expressed as big-endian (BE) or little-endian (LE), terms introduced by Danny Cohen (computer scientist), Danny Cohen into computer science for data ordering in an Internet Experiment Note published in 1980. Also published at The adjective ''endian'' has its origin in the writings of 18th century Anglo-Irish writer Jonathan Swift. In the 1726 novel ''Gulliver's Travels'', he portrays the conflict between sects of Lilliputians divided into those breaking the shell of a boiled egg from the big end or from the little end. By analogy, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Objective-C
Objective-C is a high-level general-purpose, object-oriented programming language that adds Smalltalk-style message passing (messaging) to the C programming language. Originally developed by Brad Cox and Tom Love in the early 1980s, it was selected by NeXT for its NeXTSTEP operating system. Due to Apple macOS’s direct lineage from NeXTSTEP, Objective-C was the standard language used, supported, and promoted by Apple for developing macOS and iOS applications (via their respective application programming interfaces ( APIs), Cocoa and Cocoa Touch) from 1997, when Apple purchased NeXT until the introduction of the Swift language in 2014. Objective-C programs developed for non-Apple operating systems or that are not dependent on Apple's APIs may also be compiled for any platform supported by GNU GNU Compiler Collection (GCC) or LLVM/ Clang. Objective-C source code 'messaging/implementation' program files usually have filename extensions, while Objective-C 'header/ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
String (computer Science)
In computer programming, a string is traditionally a sequence of character (computing), characters, either as a literal (computer programming), literal constant or as some kind of Variable (computer science), variable. The latter may allow its elements to be Immutable object, mutated and the length changed, or it may be fixed (after creation). A string is often implemented as an array data structure of bytes (or word (computer architecture), words) that stores a sequence of elements, typically characters, using some character encoding. More general, ''string'' may also denote a sequence (or List (abstract data type), list) of data other than just characters. Depending on the programming language and precise data type used, a variable (programming), variable declared to be a string may either cause storage in memory to be statically allocated for a predetermined maximum length or employ dynamic allocation to allow it to hold a variable number of elements. When a string appears lit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Computer Network
A computer network is a collection of communicating computers and other devices, such as printers and smart phones. In order to communicate, the computers and devices must be connected by wired media like copper cables, optical fibers, or by wireless communication. The devices may be connected in a variety of network topologies. In order to communicate over the network, computers use agreed-on rules, called communication protocols, over whatever medium is used. The computer network can include personal computers, Server (computing), servers, networking hardware, or other specialized or general-purpose Host (network), hosts. They are identified by network addresses and may have hostnames. Hostnames serve as memorable labels for the nodes and are rarely changed after initial assignment. Network addresses serve for locating and identifying the nodes by communication protocols such as the Internet Protocol. Computer networks may be classified by many criteria, including the tr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Graphical User Interface
A graphical user interface, or GUI, is a form of user interface that allows user (computing), users to human–computer interaction, interact with electronic devices through Graphics, graphical icon (computing), icons and visual indicators such as secondary notation. In many applications, GUIs are used instead of text-based user interface, text-based UIs, which are based on typed command labels or text navigation. GUIs were introduced in reaction to the perceived steep learning curve of command-line interfaces (CLIs), which require commands to be typed on a computer keyboard. The actions in a GUI are usually performed through direct manipulation interface, direct manipulation of the graphical elements. Beyond computers, GUIs are used in many handheld mobile devices such as MP3 players, portable media players, gaming devices, smartphones and smaller household, office and Distributed control system, industrial controls. The term ''GUI'' tends not to be applied to other lower-displa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Interprocess Communication
In computer science, interprocess communication (IPC) is the sharing of data between running processes in a computer system. Mechanisms for IPC may be provided by an operating system. Applications which use IPC are often categorized as clients and servers, where the client requests data and the server responds to client requests. Many applications are both clients and servers, as commonly seen in distributed computing. IPC is very important to the design process for microkernels and nanokernels, which reduce the number of functionalities provided by the kernel. Those functionalities are then obtained by communicating with servers via IPC, leading to a large increase in communication when compared to a regular monolithic kernel. IPC interfaces generally encompass variable analytic framework structures. These processes ensure compatibility between the multi-vector protocols upon which IPC models rely. An IPC mechanism is either synchronous or asynchronous. Synchronization pri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Event Loop
In computer science, the event loop (also known as message dispatcher, message loop, message pump, or run loop) is a programming construct or design pattern that waits for and dispatches events or messages in a program. The event loop works by making a request to some internal or external "event provider" (that generally blocks the request until an event has arrived), then calls the relevant event handler ("dispatches the event"). It is also commonly implemented in servers such as web servers. The event loop may be used in conjunction with a reactor, if the event provider follows the file interface, which can be selected or 'polled' (the Unix system call, not actual polling). The event loop almost always operates asynchronously with the message originator. When the event loop forms the central control flow construct of a program, as it often does, it may be termed the main loop or main event loop. This title is appropriate, because such an event loop is at the highest leve ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Graphical User Interface
A graphical user interface, or GUI, is a form of user interface that allows user (computing), users to human–computer interaction, interact with electronic devices through Graphics, graphical icon (computing), icons and visual indicators such as secondary notation. In many applications, GUIs are used instead of text-based user interface, text-based UIs, which are based on typed command labels or text navigation. GUIs were introduced in reaction to the perceived steep learning curve of command-line interfaces (CLIs), which require commands to be typed on a computer keyboard. The actions in a GUI are usually performed through direct manipulation interface, direct manipulation of the graphical elements. Beyond computers, GUIs are used in many handheld mobile devices such as MP3 players, portable media players, gaming devices, smartphones and smaller household, office and Distributed control system, industrial controls. The term ''GUI'' tends not to be applied to other lower-displa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hash Table
In computer science, a hash table is a data structure that implements an associative array, also called a dictionary or simply map; an associative array is an abstract data type that maps Unique key, keys to Value (computer science), values. A hash table uses a hash function to compute an ''index'', also called a ''hash code'', into an array of ''buckets'' or ''slots'', from which the desired value can be found. During lookup, the key is hashed and the resulting hash indicates where the corresponding value is stored. A map implemented by a hash table is called a hash map. Most hash table designs employ an Perfect hash function, imperfect hash function. Hash collision, Hash collisions, where the hash function generates the same index for more than one key, therefore typically must be accommodated in some way. In a well-dimensioned hash table, the average time complexity for each lookup is independent of the number of elements stored in the table. Many hash table designs also ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
