Reference to 'X' is ambiguous

Question

After several changes to my project I suddenly get this build error:

Reference to 'kCGImageAlphaPremultipliedLast' is ambiguous

and when when taking a look at the error it shows me that it is referenced 4 times:

Can someone please tell me how this can happen and how can I figure out what is causing this? I am not importing anything from CoreGraphics explicitly and my Prefix file only imports ´Foundation.h´ and some self made macros. I am however importing several headers containing pure C code but they are all encapsulated in something like this:

#ifndef __MYCCODE_H
#define __MYCCODE_H
// imports here
// c code here
#endif

This happens in Xcode 5 using LLVM 5.1

Edit: this seems to be a different problem with this project. after commenting this line of code I get another error:

Malformed or corrupted AST file: 'Unable to load module "/Users/xxx/Library/Developer/Xcode/DerivedData/ModuleCache/1NHZ5MC2OSMJV/CoreImage.pcm": module file out of date'

Removing the module and adding it again did not help. Deleting the derived data also didn't help. This error also appears when going back to a working commit.

Answer 1

Ok after creating a new Project and coping everything to this project the build was successful however i got this "Malformed or corrupted AST file" error several times again but it can be solved by:

• Clean the project
• Deleting everything inside '~/Library/Developer/Xcode/DerivedData/ModuleCache/' (the button inside the organizer window did not work for me)
• Clean once more
• Build project

after that it works just fine except that i have to do this fix from time to time

i also did a diff to the old project and it seems a lot of frameworks and other old stuff got stuck in there from testing things so in case you have this check your project settings file for old stuff.

i thought that xcode and me can be friends one day. guess not...

Answer 2

This's maybe you import like this:

#import "xxxx.h"

I fix it through this:

#import < xxxx/xxxx.h>

Answer 3

I have got this problem when I have imported a header file twice. After one of them is removed, the problem disappears.