---
name: "ferror"
section: "3"
platform: "linux"
package: "man-pages"
version: "6.19-1"
release: "Arch Linux 2026-11-01"
platforms: ["linux", "freebsd", "macos"]
url: "https://new.carta.tech/ferror"
---

# ferror(3)

check and reset stream status

## NAME

clearerr, feof, ferror - 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***);**

## 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 nonzero if it is set. The end-of-file indicator can be cleared only by the function **clearerr**().

The function **ferror**() tests the error indicator for the stream pointed to by *stream*, returning nonzero if it is set. The error indicator can be reset only by the **clearerr**() function.

For nonlocking counterparts, see [**unlocked\_stdio**(3)](/unlocked_stdio/3.md).

## RETURN VALUE

The **feof**() function returns nonzero if the end-of-file indicator is set for *stream*; otherwise, it returns zero.

The **ferror**() function returns nonzero if the error indicator is set for *stream*; otherwise, it returns zero.

## ERRORS

These functions should not fail and do not set *errno*.

## ATTRIBUTES

For an explanation of the terms used in this section, see [**attributes**(7)](/attributes/7.md).

| | | |
| --- | --- | --- |
| **Interface** | **Attribute** | **Value** |
| **clearerr**(), **feof**(), **ferror**() | Thread safety | MT-Safe |

## STANDARDS

C11, POSIX.1-2008.

## HISTORY

C89, POSIX.1-2001.

## NOTES

POSIX.1-2008 specifies that these functions shall not change the value of *errno* if *stream* is valid.

## CAVEATS

Normally, programs should read the return value of an input function, such as [**fgetc**(3)](/fgetc/3.md), before using functions of the [**feof**(3)](/feof/3.md) family. Only when the function returned the sentinel value **EOF** it makes sense to distinguish between the end of a file or an error with [**feof**(3)](/feof/3.md) or [**ferror**(3)](/ferror/3.md).

## SEE ALSO

[**open**(2)](/open/2.md), [**fdopen**(3)](/fdopen/3.md), [**fileno**(3)](/fileno/3.md), [**stdio**(3)](/stdio/3.md), [**unlocked\_stdio**(3)](/unlocked_stdio/3.md)