NAME
clearerr, feof,
ferror, fileno —
check and reset stream
status
LIBRARY
library “libc”
SYNOPSIS
#include
<stdio.h>
void
clearerr(FILE
*stream);
int
feof(FILE
*stream);
int
ferror(FILE
*stream);
int
fileno(FILE
*stream);
DESCRIPTION
The functionclearerr()
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
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”).