objc之method&class attributes

【objc之method&class attributes】　　

　　Objective-C now supports some gcc attributes for Objective-C methods. Syntactically, attributes for a method follow the method's declaration, and attributes for a method parameter sit between the parameter type and the parameter name. Supported attributes include:

　　Deprecation and availability, including AvailabilityMacros.h

　　- (void)method:(id)param  __attribute__((deprecated));

　　Unused parameters

　　- (void)method:(id) __attribute__((unused)) param;

　　Sentinel parameters, including NS_REQUIRES_NIL_TERMINATION

　　- (void)methodWithObjects:(id)obj, ...  NS_REQUIRES_NIL_TERMINATION;

　　Objective-C also supports some gcc attributes for Objective-C classes. Syntactically, attributes for a class precede the class's @interface declaration. Supported attributes include:

　　Deprecation and availability, including AvailabilityMacros.h

　　__attribute__((deprecated))

　　@interface MyDeprecatedClass : SomeSuperclass

　　Visibility

　　__attribute__((visibility("hidden")))

　　@interface MyPrivateClass : SomeSuperclass