How to add CIFilter to CALayer

I am new to core animation , i add some layers to my view and add image to it. Now i want to give blur effect to my layer

But i don't know how to make CIFilter and add it. I go through the related questions Question 1 Question2

My code is given below (Shows compilation error)

#import < UIKit/UIKit.h >
#import < QuartzCore/QuartzCore.h >
#import < CoreGraphics/CoreGraphics.h >


@interface T_CALayerPart3_View : UIView {

    CALayer *_layer1;
    CALayer *_layer2;
    CALayer *_layer3;
    CALayer *_layer4;
    CALayer *_layer5;
    CIFilter *_filter;    //<----- error here[Expected specifier -qualifier -list before CIFilter]

    CATransform3D *_rotate, *_scale;

}
@end

Give me some suggestion. Your suggestion is important to me. Don't leave the page without any Answer/ comment.

[sorry for my poor English]

Copyright Notice：Content Author:「new_programmer」，Reproduced under the CC 4.0 BY-SA copyright license with a link to the original source and this disclaimer.
Link to original article：https://stackoverflow.com/questions/3737577/how-to-add-cifilter-to-calayer