Carbon (API)

Apple did not create a 64-bit version of Carbon while updating their other frameworks in the 2007 time-frame, and eventually deprecated the entire API in OS X 10.8 Mountain Lion, which was released on July 24, 2012.

Much of the Macintosh Toolbox consisted of procedure calls, passing information back and forth between the API and program using a variety of data structures based on Pascal's variant record concept.

With the purchase of NeXT in late 1996, Apple developed a new operating system strategy based largely on the existing OPENSTEP for Mach platform.

The new Rhapsody OS strategy was relatively simple; it retained most of OpenStep's existing object libraries under the name "Yellow Box", ported the existing GUI in OPENSTEP for Mach and made it look more Mac-like, ported several major APIs from the Mac OS to Rhapsody's underlying Unix-like system (notably QuickTime and AppleSearch), and added an emulator known as the "Blue Box" that ran existing Mac OS software.

[citation needed] Larger developers like Microsoft and Adobe balked outright, and refused to consider porting to OpenStep, which was so different from the existing Mac OS that there was little or no compatibility.

In order to offer a real and well supported upgrade path for existing Mac OS code bases, Apple introduced the Carbon system.

This allowed Carbon to support true multitasking and memory protection, features Mac developers had been requesting for a decade.

Other changes from the pre-existing API removed features which were conceptually incompatible with Mac OS X, or simply obsolete.

This version allowed developers to port their code to Carbon without losing the ability for those programs to run on existing Mac OS machines.

[3] The transition to 64-bit Macintosh applications beginning with Mac OS X v10.5, released October 26, 2007, brought the first major limitations to Carbon.

Apple does not provide compatibility between the Macintosh graphical user interface and the C programming language in the 64-bit environment, instead requiring the use of the Objective-C dialect with the Cocoa API.

This also extended to Apple's own flagship software packages, as iTunes[8] and Final Cut Pro (as well as the features in the QuickTime engine that powers it[9]) remained written in Carbon for many years.

Carbon consists of a broad set of functions for managing files, memory, data, the user interface, and other system services.

As an umbrella term encompassing all C-language API procedures accessing Mac-specific functionality, Carbon is not designed as a discrete system.

Binary compatibility between Mac OS X and previous versions requires use of a Preferred Executable Format file, which Apple never supported in their Xcode IDE.

In order for such timers to have reasonable resolution, developers could not afford WaitNextEvent to delay too long, and so low "sleep" parameters were usually set.

This results in highly inefficient scheduling behavior, since the thread will not sleep for very long, instead repeatedly waking to return these idle events.