On Aug 6, 2008, at 5:47 AM, patrick machielse wrote:

typedef NSString MyString;

[...]

In IB the value binding of an NSTextField is connected to the Model's 'text' property. This works as expected when the code is compiled as Objective-C++. Changing to Objective-C still compiles perfectly, but when the application starts an exception is thrown inside -[Model valueForUndefinedKey:]. This puzzled me, and it took me a while to realize that the typedef seemed to be causing this behavior.

[...]
Should I have expected this?

This is obscure enough that I wouldn't have any particular expectation one way or another, I guess.

Out of curiosity, what do @encode(MyString*) and @encode(MyString) provide in Objective-C vs. Objective-C++?

I know that Key-Value Coding investigates return and parameter types of the accessors to figure out whether it needs to wrap non-objects in NSValue or NSNumber. See: <http://developer.apple.com/documentation/Cocoa/Conceptual/KeyValueCoding/Concepts/DataTypes.html >. Also see the notes under "Support for Arbitrary Types in KVC and KVO" in the Leopard Foundation release notes <http://developer.apple.com/releasenotes/Cocoa/Foundation.html#KVCKVO >.

I suspect KVC uses @encode() or its equivalent to make these inquiries. The compiler may produce different encodings for your typedef depending on the language in use.

Cheers,
Ken
_______________________________________________

Cocoa-dev mailing list ([email protected])

Please do not post admin requests or moderator comments to the list.
Contact the moderators at cocoa-dev-admins(at)lists.apple.com

Help/Unsubscribe/Update your Subscription:
http://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com

This email sent to [EMAIL PROTECTED]

Reply via email to