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 9.4