Cocoa Warning: Implicitly declaring C library function ‘objc_getClass’

In Slider 2, I needed to check for the presence for Sparkle, and only load Slider 2′s included version when Sparkle isn’t found.

The code I used to do this is included below, but the point of this article is really to provide a solution to the following warning I encountered:

warning: Semantic Issue: Implicitly declaring C library function 'objc_getClass' with type 'id (const char *)'

One will get this warning if using code when checking for the existence of a class like:

if (!objc_getClass("SUUpdater")) { ... }

The solution is to use NSClassFromString instead:

if (!NSClassFromString(@"SUUpdater")) { ... }

For an in-depth tutorial on how to check for the presence of a framework within a Cocoa bundle, see Detecting Presence of a Framework Within an NSBundle (Plugin).

Related posts:

1. Detecting Presence of a Framework Within an NSBundle (Plugin) Introduction Jump to Tutorial In light of Cocoa Warning: Implicitly declaring C library function ‘objc_getClass’, this tutorial has been updated. Recently, it was brought to my attention that my method...
2. Sliding Modal Dialogs in Cocoa Applications & Bundles Example project available on GitHub – CIModalSheetDialog One thing I wanted to be able to use during the development of Slider 2 was modal dialogs that slide out from the...

Tags: Cocoa, NSClassFromString, objc_getClass