google-objective-c-style

Method names start lowercase with mixed case and should read like a sentence, with accessors named after the attribute without a get prefix. Category files use ClassName+CategoryName.h, and category methods get a lowercase prefixed underscore form like gtm_myMethod: to avoid collisions.

Initializers and setters should copy objects that have mutable variants rather than retaining them, and synthesized accessors use the copy keyword. Delegates and targets should be held weakly to avoid retain cycles, and blocks used as callbacks must be explicitly released.

No, the guide explicitly states it must not be used as a Swift style guide. It covers Objective-C and Objective-C++ only; within Objective-C++ files, C++ methods follow the C++ style guide's naming rules.

No, code should never @throw Objective-C exceptions, though @try/@catch is allowed for third-party calls that throw. The NSObject +new method must not be invoked or overridden; use +alloc and -init instead.

Unsigned integers cause subtle errors in math and countdown-to-zero loops, so signed integers are required in arithmetic except when matching NSUInteger in system interfaces. Unsigned types remain acceptable for flags and bitmasks, though NS_OPTIONS or NS_ENUM is often preferable.