Mapping extensions and UTI on OS X

In OS X, an extension can correspond to one or more UTIs. The sample code gives an array for an extension.

NSArray *UTIs = (NSArray *)UTTypeCreateAllIdentifiersForTag(kUTTagClassFilenameExtension,
(CFStringRef)extension,
nil);

So for e1 there can be u1, u2, u3,…

Now there is a case where e1, e2, e3 correspond to the same u1.

So I have 2 questions:

Is there a case where we have the following situation?
```
u1: e1,e2,e3
u2: e1,e4,e5
u3: e4,e6
```
Based on this, if I have to set a default application for e1, which can be only set if I get u1 and u2, will this work properly?

slhck
31.4k54162

asked Feb 1 at 17:47

	To prevent premature close votes: This question contains sample code, but appears to be on topic as a whole. – Daniel Beck Feb 1 at 17:49
	Manish, are you asking about general system behavior, or specifically about the the Objective-C APIs you're using? – Daniel Beck Feb 1 at 17:53
	I wrote a snippet of code to highlight that there can be multiple UTI's for a single extension. – Manish Feb 2 at 2:05
	So I am asking about a general system behavior and what logic OSX implements for setting a default application. – Manish Feb 2 at 2:06

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