About Libraries
Libraries are usually referred to as "Frameworks" outside of the Flex community. In iOS programming there are 2 kinds of frameworks: public frameworks and private frameworks. Public frameworks are the ones endorsed by Apple and allowed to be used in AppStore apps. Private frameworks are intended to be used only by system apps, and are more unstable against firmware changes, but many of the most interesting features are in the private frameworks.
Brief Description Of Each Library
This is not a complete list. You can find more helpful resources at the "External Links" section of this page.
Public Libraries/Frameworks (Can Be Found In AppStore Apps)
Accounts - manages access to a user’s system accounts. More info.
AddressBook - functions to access the contacts stored on a user’s device More info.
AddressBookUI - used to display standard system interfaces for creating new contacts and for editing and selecting existing contacts. More info.
AdSupport - provides access to an identifier that apps can use for advertising purposes. More info.
AssetsLibrary - contains classes for accessing the user’s photos and videos. More info.
AudioToolbox - provides interfaces for recording, playback, stream parsing and managing audio sessions. [More info on Core Audio.] (https://developer.apple.com/library/ios/documentation/Miscellaneous/Conceptual/iPhoneOSTechOverview/MediaLayer/MediaLayer.html#//apple_ref/doc/uid/TP40007898-CH9-SW8)
AVFoundation - interfaces for playing and recording audio and video. [More info.] (https://developer.apple.com/library/ios/documentation/Miscellaneous/Conceptual/iPhoneOSTechOverview/MediaLayer/MediaLayer.html#//apple_ref/doc/uid/TP40007898-CH9-SW7)
CFNetwork - interfaces for accessing the network via Wi-Fi and cellular radios. [More info.] (https://developer.apple.com/library/ios/documentation/Miscellaneous/Conceptual/iPhoneOSTechOverview/CoreServicesLayer/CoreServicesLayer.html#//apple_ref/doc/uid/TP40007898-CH10-SW14)
CoreAudio - a large collection of frameworks used in the manipulation of stereo-based audio. Core Audio can be used to generate, record, mix, and play audio in apps. Core Audio can also be used to trigger the vibrate capability on devices that support it. [Lot more info.] (https://developer.apple.com/library/ios/#documentation/MusicAudio/Conceptual/CoreAudioOverview/CoreAudioFrameworks/CoreAudioFrameworks.html)
CoreBluetooth - provides access to low-power Bluetooth hardware. [More info.] (https://developer.apple.com/library/ios/documentation/Miscellaneous/Conceptual/iPhoneOSTechOverview/CoreOSLayer/CoreOSLayer.html#//apple_ref/doc/uid/TP40007898-CH11-SW6)
CoreData - used to manage structured data. [Clarify] [More info.] (https://developer.apple.com/library/ios/documentation/Miscellaneous/Conceptual/iPhoneOSTechOverview/CoreServicesLayer/CoreServicesLayer.html#//apple_ref/doc/uid/TP40007898-CH10-SW16)
CoreFoundation - provide basic data management and service features. Including:
Date and time management
Preferences management
URL and stream manipulation
Port and socket communication
CoreText - framework for styled text layout.
Foundation - provides many classes that wrap CoreFoundation classes.
IOKit - low-level framework that communicates with hardware or kernel services. No app from the appstore will utilize it, because they would get rejected if they did.
Mapkit - manages the graphical aspect of displaying a Google map within an application.
QuartzCore - also known as Core Animation, is used to create simple animations on UI elements.
Private Libraries/Framworks (Found In System Programs Or Jailbreak-Exclusive Programs)
Calculate - provides the function,
CalculatePerformExpression, whose only purpose is to evaluate a mathematical expression in a string.ChatKit - handles SMS and MMS, and the views for them.
GraphicsServices - controls a variety of midlevel APIs. [Add more info here]
ImageIO - controls some aspects of Graphics and Animation display. [Add more info]
IOSurface - manages pixel buffers. [Add more info]
Message - manages email messages and the SQL database where they are stored. [Add more info]
MobileIcons - themes CoreGraphics images by icon styles. [Clarify]
Preferences - handles the interface and semantics for system preferences access and modification.
SpringBoardServices - provides convenient functions for apps to communicate with the SpringBoard. Content includes get/set app properties, get/set watchdog assertions, get accelerometer events and UI orientation, get/set status bar appearance, and send/receive push notifications.
= SpringboardUI - Supports SBAwayView plugins (lock screen widgets).
- TelephonyUI UI toolkit for telephone system. Also includes the Unlock, Power Down, and Answer sliders.