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iOS 13 Programming Fundamentals with Swift
book

iOS 13 Programming Fundamentals with Swift

by Matt Neuburg
October 2019
Intermediate to advanced content levelIntermediate to advanced
677 pages
18h 28m
English
O'Reilly Media, Inc.
Content preview from iOS 13 Programming Fundamentals with Swift

Appendix A. C, Objective-C, and Swift

The APIs for Cocoa and its associated frameworks are written in Objective-C or its underlying base language, C. Messages that you send to Cocoa using Swift are being translated for you into Objective-C. Objects that you send and receive back and forth across the Swift/Objective-C bridge are Objective-C objects. Some objects that you send from Swift to Objective-C are even being translated for you into other object types, or into nonobject types.

This appendix summarizes the relevant linguistic features of C and Objective-C, and describes how Swift interfaces with those features. I do not explain here how to write Objective-C! For example, I’ll talk about Objective-C methods and method declarations, because you need to know how to call an Objective-C method from Swift; but I’m not going to explain how to call an Objective-C method using Objective-C.

The C Language

Objective-C is a superset of C; to put it another way, C provides the linguistic underpinnings of Objective-C. Everything that is true of C is true also of Objective-C. It is possible, and often necessary, to write long stretches of Objective-C code that are, in effect, pure C. Some of the Cocoa APIs are written in C. Therefore, in order to know about Objective-C, it is necessary to know about C.

C statements, including declarations, must end in a semicolon. Variables must be declared before use. A variable declaration consists of a data type name followed by the variable name, optionally ...

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Publisher Resources

ISBN: 9781492074526Errata Page