How To Use macro without importing the .h file in the Xcode

Question

Someday, I found one issue in the Xcode. I used one macro for anywhere I want, the problem is I was't imported one .h file where the macro defined, in fact I can use this macro normally. Can somebody help me?

What is the problem you try to solve? Circular imports? Then use [`@class`](http://stackoverflow.com/questions/5191487/objective-c-forward-class-declaration). Or do you want do save typing work? Then look for the [precompiled header](http://stackoverflow.com/questions/6707590/is-there-a-place-to-put-a-category-import-statement-so-all-classes-see-it/6707627#6707627) — Matthias Bauch, Oct 11 '13 at 07:14

score 0 · Accepted Answer · edited May 23 '17 at 10:29

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Import to the precompiled header file *.pch in your project, that way it will be imported to any implementation file automatically. See here

edited May 23 '17 at 10:29

Community

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answered Nov 14 '13 at 12:27

suydea

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Though it's best not to mess with the .pch file unless you need that macro in 90% of your controllers). – Lord Zsolt Nov 14 '13 at 13:00

Vaibhav Saran · Answer 2 · 2013-11-14T13:04:26.133

defining any macro inside <your project>.pch will work for entire app automatically. You can find this auto-generated file inside Supporting Files in your project directory.

In .pch file you should declare all those constants and and macros you are using throughout the app (not recommended if you are not using these variables in most of the viewcontrollers) and in most of the viewControllers

for example:

// frameworks
#import <UIKit/UIKit.h>
#import <Foundation/Foundation.h>

// a category
#import "UIColor+custom.h"

// a class
#import "aClass.h"

 // a macro
#define kAppFont @"TrebuchetMS"

// a global object
NSInteger myInteger; 

// a macro with case
#define IS_IPHONE_5 ( fabs( ( double )[ [ UIScreen mainScreen ] bounds ].size.height - ( double )568 ) < DBL_EPSILON )

How To Use macro without importing the .h file in the Xcode

2 Answers2