taglib/taglib — pull request #38 by robinst (2012-06-10 13:36:46+00:00)
Title: Fix docs of MPEG::File::ID3v(1|2)Tag for inexistent tag

Since 37e2d629, the ID3v1 and ID3v2 tags are always created at the end
of MPEG::File::read. So contrary to what the documentation said, a null
pointer is never returned.

To check if a tag contains data, refer to isEmpty() in the
documentation.

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I was confused by this while working with TagLib and apparently others too:

http://stackoverflow.com/questions/4404705/unexpected-non-null-return