FERROR(3)

NAME
clearerr, feof, ferror, fileno - check and reset stream status

LIBRARY
libc

SYNOPSIS
#include <stdio.h>
void
clearerr(FILE *stream);
int
feof(FILE *stream);
int
ferror(FILE *stream);
int
fileno(FILE *stream);

DESCRIPTION
The function clearerr() clears the end-of-file and error indicators for the stream pointed to by stream.

The function feof() tests the end-of-file indicator for the stream pointed to by stream, returning non-zero if it is set. The end-of-file indicator can only be cleared by the function clearerr().

The function ferror() tests the error indicator for the stream pointed to by stream, returning non-zero if it is set. The error indicator can only be reset by the clearerr() function.

The function fileno() examines the argument stream and returns its integer descriptor.

ERRORS
The functions clearerr(), feof(), and ferror() should neither fail nor set the external variable errno. However, the function fileno() may fail and return -1 in case the argument stream is not associated with a valid file descriptor. (In this case the NetBSD implementation does not follow the optional POSIX recommendation to set the errno variable to EBADF.)

SEE ALSO
open(2), stdio(3)

STANDARDS
The functions clearerr(), feof(), and ferror() conform to ansiC. The function fileno() conforms to p1003.1-90.