---
name: "fclose"
section: "3"
platform: "freebsd"
package: "base"
version: "16.0-CURRENT-20261027-61c70dc16a79"
release: "FreeBSD 16.0-CURRENT (2026-10-27)"
platforms: ["linux", "freebsd", "macos"]
url: "https://new.carta.tech/fclose"
---

# fclose(3)

close a stream

## NAME

**fclose**, **fdclose**, **fcloseall** – close a stream

## LIBRARY

Standard C Library (libc, -lc)

## SYNOPSIS

**#include \<stdio.h\>**

*int*\

**fclose**(*FILE \*stream*);

*int*\

**fdclose**(*FILE \*stream*, *int \*fdp*);

*void*\

**fcloseall**(*void*);

## DESCRIPTION

The **fclose**() function dissociates the named *stream* from its underlying file or set of functions. If the stream was being used for output, any buffered data is written first, using [fflush(3)](/fflush/3.md).

The **fdclose**() function is equivalent to **fclose**() except that it does not close the underlying file descriptor. If *fdp* is not NULL, the file descriptor will be written to it. If the stream does not have an associated file descriptor, *fdp* will be set to -1. This type of stream is created with functions such as [fmemopen(3)](/fmemopen/3.md), [funopen(3)](/funopen/3.md), or [open\_memstream(3)](/open_memstream/3.md).

The **fcloseall**() function calls **fclose**() on all open streams.

## RETURN VALUES

**fcloseall**() does not return a value.

Upon successful completion the **fclose**() and **fdclose**() functions return 0. Otherwise, EOF is returned and the global variable *errno* is set to indicate the error.

## ERRORS

**fdclose**() fails if:

- \[EOPNOTSUPP\]

  The stream does not have an associated file descriptor.

The **fclose**() and **fdclose**() functions may also fail and set *errno* for any of the errors specified for [fflush(3)](/fflush/3.md).

The **fclose**() function may also fail and set errno for any of the errors specified for [close(2)](/close/2.md).

## NOTES

The **fclose**() and **fdclose**() functions do not handle NULL arguments in the *stream* variable; this will result in a segmentation violation. This is intentional. It makes it easier to make sure programs written under FreeBSD are bug free. This behaviour is an implementation detail, and programs should not rely upon it.

## SEE ALSO

[close(2)](/close/2.md), [fflush(3)](/fflush/3.md), [fopen(3)](/fopen/3.md), [setbuf(3)](/setbuf/3.md)

## STANDARDS

The **fclose**() function conforms to ISO/IEC 9899:1990 (“ISO C90”).

## HISTORY

The **fcloseall**() function first appeared in FreeBSD 7.0.

The **fdclose**() function first appeared in FreeBSD 11.0.