{"id":27298,"date":"2019-11-19T15:53:42","date_gmt":"2019-11-19T20:53:42","guid":{"rendered":"https:\/\/mjtsai.com\/blog\/?p=27298"},"modified":"2019-12-17T16:31:10","modified_gmt":"2019-12-17T21:31:10","slug":"direct-objective-c-properties","status":"publish","type":"post","link":"https:\/\/mjtsai.com\/blog\/2019\/11\/19\/direct-objective-c-properties\/","title":{"rendered":"Direct Objective-C Properties"},"content":{"rendered":"

In a future compiler version<\/a>:<\/p>\n

A direct<\/code> property specifier is added (@Property(direct) type name<\/code>)<\/p>\n

These attributes \/ specifiers cause the method to have no associated\nObjective-C metadata (for the property or the method itself), and the\ncalling convention to be a direct C function call.<\/p>\n

The symbol for the method has enforced hidden visibility and such direct\ncalls are hence unreachable cross image. An explicit C function must be\nmade if so desired to wrap them.<\/p><\/blockquote>\n

Via Tanner Bennett<\/a>:<\/p>\n

This feature tries it’s hardest to break everything that makes Objc great. KVC, KVO, swizzling, etc., even OOP because this is effectively final<\/code> for objc. In case anyone was wondering why I’m disappointed in this addition.<\/p>\n

I can only hope codebases adopt it sparingly.<\/p><\/blockquote>\n

Greg Parker<\/a>:<\/p>\n

\n

Counterargument: the alternative to get this level of performance is to rewrite your method as a C function. That experience is awful in practice. It’s important to be able to tune dynamism vs performance without busy-work syntax changes.<\/p>\n<\/blockquote>\n

It’s a great feature to have for this reason. But I hope it’s not overused.<\/p>\n\n

Previously:<\/p>\n