ferror, feof, clearerr, fileno - stream status inquiries
int feof(FILE *stream)
int ferror(FILE *stream)
int clearerr(FILE *stream)
int fileno(FILE *stream)
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 stream.
Fileno returns the integer file descriptor associated with the stream,
Currently all of these functions are implemented as macros; they cannot