How to deprecate a method in Objective-C

We have our library we ship to our customers, and I'd like to mark some meth开发者_开发百科ods as "deprecated" because we changed them (like Apple does in the iPhone SDK).

I've seen the __OSX_AVAILABLE_BUT_DEPRECATED pre-processor macro, which is mapped to __AVAILABILITY_INTERNAL, which is mapped to __attribute__((deprecated))...

Well i'm a bit confused with this stuff!

Anybody knows something about that ?

---

__attribute__((deprecated)) is the gcc way (also supported in clang) of marking a function / method as deprecated. When one is marked as "deprecated", a warning will be produced whenever anyone calls it.

The syntax for normal functions would be

__attribute__((deprecated))
void f(...) {
  ...
}

// gcc 4.5+ / clang
__attribute__((deprecated("g has been deprecated please use g2 instead")))
void g(...) {
  ...
}

and that of Objective-C methods would be

@interface MyClass : NSObject { ... }
-(void)f:(id)x __attribute__((deprecated));
...
@end

You can also mark the whole class as deprecated with

__attribute__((deprecated))
@interface DeprecatedClass : NSObject { ... }
...
@end

---

Apple also provides the <AvailabilityMacros.h> header which provides the DEPRECATED_ATTRIBUTE and DEPRECATED_MSG_ATTRIBUTE(msg) macros that expand to the above attributes, or nothing if the compiler doesn't support attributes. Note that this header doesn't exist outside of OS X / iOS.

---

Side note, if you are using Swift you use the @available attribute to deprecate an item, e.g.

@available(*, deprecated=2.0, message="no longer needed")
func f() {
    ...
}

---

You can also use more readable define DEPRECATED_ATTRIBUTE

It defined in usr/include/AvailabilityMacros.h:

#define DEPRECATED_ATTRIBUTE        __attribute__((deprecated))
#define DEPRECATED_MSG_ATTRIBUTE(msg) __attribute((deprecated((msg))))

Objective-C methods example:

@interface MyClass : NSObject { ... }
-(void)foo:(id)x DEPRECATED_ATTRIBUTE;

// If you want to specify deprecated message:
-(void)bar:(id)x DEPRECATED_MSG_ATTRIBUTE("Use baz: method instead.");
...
@end

You can also mark the whole class as deprecated:

DEPRECATED_ATTRIBUTE
@interface DeprecatedClass : NSObject { ... }
...
@end

---

Swift 5.0

Deprecate any method/class/struct/protocols using @available

@available(*, deprecated, message: "Parse your data by hand instead")
func parseData() { }

@available(*, deprecated, renamed: "loadData")
func fetchData() { }

@available(swift, obsoleted: 4.1, renamed: "attemptConnection")
func testConnection() { }

@available(swift, deprecated: 4.0, obsoleted: 5.0, message: "This will be removed in v5.0; please migrate to a different API.")

Possible params:

• introduced
• deprecated
• obsoleted
• message
• renamed

For more info see apple doc: Attributes

---

If you are using C++14 in your xcode project, you may also use the [[deprecated]] or [[deprecated("reason")]] attribute that is now part of the language.

see documentation: http://en.cppreference.com/w/cpp/language/attributes

---

- FOR SWIFT CODE:

Put this right above the method: @available(*, deprecated: <#Version#>, message: <#Message#>)

example:

@available(*, deprecated: 11, message: "Use color assets instead")
public struct ColorPaletteItemResource: ColorPaletteItemResourceType {
    ...
}