_read() results in invalid errno

[gogolion]

I have an application that is showing some strange behavior after
some
recent code changes. Part of the application is reading data from
files. Recently the call to _read() has begun failing with errno set
to 2 (ENOENT - No such file or directory) or 13 (EACCES - permission
denied). Neither of these errno values make sense in the context of
reading from a file handle that was successfully opened. In
addition,
the help on _read() says that EBADF and EINVAL are the only valid
errno values for a failed _read() call.

Does anyone have any clue what these other errno values may mean in
this context?

Thanks in advance