FERROR(3)

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”).

May 6, 2010 | NetBSD 8.0