documentation references from xcode

As someone new to C and iPhone development, I'm making lots of use of the documentation.

The "doc sets" pull down has only "iPhone OS3.1" library selected.

However, sometimes when I highlight text in my source - eg "sqrt", right click, and choose "find text in documentation" I get a bunch of "Mac OSX Manual Page" hits, with pages titled "BSD Library Functions Manua开发者_C百科l".

Do I have some configuration setting wrong?

Thanks,

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It's not actually in the docs. Use go to edit: declaration to see it. Things like that (e.g. M_PI) are usually pretty self explanatory.