Updated: 2022/Sep/29

Please read Privacy Policy. It's for your privacy.

FERROR(3)                  Library Functions Manual                  FERROR(3)

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

LIBRARY
     Standard C Library (libc, -lc)

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 ANSI
     X3.159-1989 ("ANSI C89").  The function fileno() conforms to IEEE Std
     1003.1-1990 ("POSIX.1").

NetBSD 10.99                      May 6, 2010                     NetBSD 10.99