Question

I’m getting the following linker errors when I try to use CIFilter in iOS 5.

Undefined symbols for architecture i386: "_OBJC_CLASS_$_CIFilter", referenced from: objc class-ref in libios_ngn_stack.a(NgnProxyVideoConsumer.o)"_kCIInputImageKey", referenced from:

The line that causes the error is:

CIFilter *filter = [CIFilter filterWithName:@"CISepiaTone" 
                                          keysAndValues: kCIInputImageKey, image, 
                                @"inputIntensity", [NSNumber numberWithFloat:0.8], nil];

Somebody had the same issue in this question, but the only answer was that he need sLibrary/Frameworks/CoreImage.framework. Could somebody elaborate on how I would go about installing this ramework? (I do have a CoreImage framework in Library/Frameworks/QuartzCore/Frameworks/CoreImage…)

Any help would be appreciated

Answer 1

In Xcode 4.x, simply go to your project settings, click on your target, click on the Build Phases tab, and expand the Link Binary With Libraries group. When you click on the plus button there, you will be presented with a list of libraries to link against.

Find CoreImage.framework in that list (you can filter using the upper search area) and click on Add to add it to the list of linked libraries for your application.