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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,

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:

  1. Is there a case where we have the following situation?

    u1: e1,e2,e3
    u2: e1,e4,e5
    u3: e4,e6
  2. 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?

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To prevent premature close votes: This question contains sample code, but appears to be on topic as a whole. – Daniel Beck Feb 1 '12 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 '12 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 '12 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 '12 at 2:06

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