Use C definitions in Objective-C

Question

I would define some helper functions, and i prefer write them in C instead of objective-C.

Which is the "best practice" to add header and implementation C file in a Objective C project ?

If i need to use Objective-c definition in my functions, what i need to include in my header C file (UIKit?) ?

Example: i'd like to create a shortcut to NSLog for NSString , can i create in my C file something similar to this code ? :

void MYLog (NSString *string){
  NSLog(@"%@",string);
}

Why create a shortcut for NSLog() to take a single NSString when it already take a string, and optionaly more parameters? — PeyloW
– PeyloW, Commented Dec 15, 2010 at 12:47
Every time I've thought I'll just create a C API here, I've regretted it... An Objective-C version isn't that much more work, rarely incurs a significant amount of overhead vs. straight C and is considerably more versatile. — bbum
– bbum, Commented Dec 15, 2010 at 16:32
ehm... Peylow you are right is completely useless ...let's say this is an example to help me formulate the question :P -.- — MatterGoal
– MatterGoal, Commented Dec 23, 2010 at 20:58

Vladimir · Accepted Answer · 2010-12-15 11:12:34Z

2

Yes sure you can use objective-c functions in your c code (and vice versa) if your source file is compiled as c/obj-c code (has .m extension or type set manually in xcode)

To make core functions work I think importing <Foundation/Foundation.h> and <UIKit/UIKit.h> should be sufficient. These headers may be already imported in your precompiled header (*.pch file) so you may not even need to import them.

If you want to extend some UIKit classes functionality consider also implementing custom class category instead of using plain c functions.

edited Dec 15, 2010 at 11:12

answered Dec 15, 2010 at 10:34

Vladimir

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1 Comment

JeremyP Over a year ago

And put your C code in a .m file so things like @"foo" are understood by the compiler

zoul · Accepted Answer · 2010-12-15 10:36:10Z

0

You can do this quite easily. You shouldn’t have to import anything, as you have UIKit and Foundation already imported by the prefix header. The logger function would look like this:

// Logger.h
void MyLog(NSString *str);

// Logger.m
#import "Logger.h"
void MyLog(NSString *str) {…}

answered Dec 15, 2010 at 10:36

zoul

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2 Comments

MatterGoal Over a year ago

Thank you zoul, in your opinion, can i work with .c extension or i need to use .m ?

zoul Over a year ago

You should use .m, so that the compiler understands Objective-C in those files.

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