ferror, feof, clearerr, fileno - stream status inquiries
Feof returns non-zero when end of file is read on the named input
stream, otherwise zero. Unless cleared by clearerr, the end-of-
file indication lasts until the stream is closed.
Ferror returns non-zero when an
error has occurred reading or
writing the named stream, otherwise zero. Unless cleared by
clearerr, the error indication lasts until the stream is closed.
Clearerr resets the error and
end-of-file indicators on the named
Fileno returns the integer file
descriptor associated with the
stream, see open(2).
Currently all of these functions
are implemented as macros; they
cannot be redeclared.