FERROR(3) | Library Functions Manual | FERROR(3)

# NAME

`clearerr`, `feof`, `ferror`, `fileno` — check and reset stream status

# 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 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`() returns the file descriptor associated with the given stream or -1 if it is not associated with any file descriptor, for example if it was created with fmemopen(3), open_memstream(3), or funopen(3).

# ERRORS

These functions should not fail and do not set the external variable errno.

# 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”).

# HISTORY

The functions `clearerr`(), `feof`(), `ferror`(), and `fileno`() first appeared in Version 7 AT&T UNIX.

October 31, 2021 | Debian