How do I flag a function as being deprecated in an iOS Objective-C header file?

Question

I'm guessing there's just some keyword I can stick after the function somewhere?

I would like for a compiler warning to be generated should anyone try and use the deprecated function, similar to the behavior seen in Apple's APIs.

Hey gs - good comment. I was actually thinking this just now! — Nick Cartwright, Sep 18 '09 at 11:56

score 62 · Accepted Answer · edited Apr 15 '11 at 19:57

62

Try appending an attribute to your method declaration:

- (void)fooBar __attribute__ ((deprecated));

Taken from here.

edited Apr 15 '11 at 19:57

Andrew

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answered Sep 18 '09 at 12:36

Tim

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Looks like pretty ugly syntax - but if it works, it works! Thanks Tim. – Nick Cartwright Sep 19 '09 at 16:21
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you may _#define DEPRECATED _____attribute_____ ((deprecated))_ – Denis Mikhaylov Feb 11 '12 at 07:03
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- (void)fooBar DEPRECATED_ATTRIBUTE; works for me. I don't think you need the #define as Denis suggested, it's already defined AFAIK – pshah Jun 29 '12 at 17:42
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or you can simply use __deprecated – ArtFeel Feb 25 '13 at 13:24
Huh. Appending `__deprecated` to a method declaration works too, and I have no idea why. Thanks for the suggestion, @ArtFeel - do you happen to know where that's defined? – Tim Feb 25 '13 at 17:18
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this defined in [cdefs.h](http://www.opensource.apple.com/source/xnu/xnu-1456.1.26/bsd/sys/cdefs.h) – ArtFeel Feb 27 '13 at 15:13
Awesome, thanks. Works like I expected - a `#define` to the attribute. – Tim Feb 27 '13 at 17:29
Awesome, just using __deprecated - works for @property too. Thanks. – GreenKiwi Apr 01 '13 at 21:04

Cœur · Answer 2 · 2016-05-05T02:52:22.303

Instead of __attribute__((deprecated)), you can use use the macros defined in <cdefs.h>:

- (void)fooBar __deprecated;
// Or better:
- (void)fooBar __deprecated_msg("Use barFoo instead.");

Or you can use the macros defined in <AvailabilityMacros.h>:

- (void)fooBar DEPRECATED_ATTRIBUTE;
// Or better:
- (void)fooBar DEPRECATED_MSG_ATTRIBUTE("Use barFoo instead.");

If you use Objective-C, it makes no difference as you are going to use a modern compiler, so you can go for Apple short syntax __deprecated_msg(). But if you use C for cross-platform, then DEPRECATED_MSG_ATTRIBUTE() uses the optimal availability definitions (for instance, it supports GCC3.1).

score 7 · Answer 3 · answered Sep 18 '09 at 20:30

Tim's answer will actually produce a compiler warning; the other versions are merely comments which have no effect w.r.t. the compiler.

If you look at /usr/include/AvailabilityMacros.h, you'll see how Apple does this. That header uses __attribute__((deprecated)) and __attribute__((unavailable)) depending on whether the API is present but deprecated, or has actually been removed from the OS.

score 2 · Answer 4 · answered Sep 18 '09 at 10:15

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From Apple's SFAuthorization.h:

/*!
DEPRECATED: Use obtainWithRight:flags:error:
@method permitWithRight:flags:
@abstract Call permitWithRight to gain a right to have
          access to a privilege operation.
@param rightName The name of an authorization right.
@param flags Authorization flags.
*/
- (OSStatus)permitWithRight:(AuthorizationString)rightName
                      flags:(AuthorizationFlags)flags;

If you're not using an automated documentation builder I'd say something like this is enough:

- (void)doSomething;           /* DEPRECATED */

answered Sep 18 '09 at 10:15

Georg Schölly

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Thanks for the comment. If I use the 'permitWithRight' function in SFAuthorization, I get a compiler warning... Is there a way to add a deprecation flag to give compiler warnings? – Nick Cartwright Sep 18 '09 at 12:01
You could use the preprocessor's command #warning, but it's not standard and likely to not work in all compilers. See http://stackoverflow.com/questions/171435/portability-of-warning-preprocessor-directive – Georg Schölly Sep 18 '09 at 12:54

score 2 · Answer 5 · answered Sep 18 '09 at 13:37

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You could also follow the HeaderDoc manual. Where this syntax is used:

/*!
 * @abstract Foo is good for bar.
 *
 * @deprecated in version 2.0
 */

answered Sep 18 '09 at 13:37

PeyloW

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How do I flag a function as being deprecated in an iOS Objective-C header file?

5 Answers5

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