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

# getpagesize(3)

get system page size

## NAME

**getpagesize** – get system page size

## LIBRARY

Standard C Library (libc, -lc)

## SYNOPSIS

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

*int*\

**getpagesize**(*void*);

## DESCRIPTION

The **getpagesize**() function returns the number of bytes in a page. Page granularity is the granularity of many of the memory management calls.

The page size is a system page size and may not be the same as the underlying hardware page size.

IEEE Std 1003.1-2001 (“POSIX.1”) removed **getpagesize**. Portable applications should use ‘sysconf(\_SC\_PAGESIZE)’ instead.

## SEE ALSO

[pagesize(1)](/pagesize/1.md), [sbrk(2)](/sbrk/2.md), [getpagesizes(3)](/getpagesizes/3.md), [sysconf(3)](/sysconf/3.md)

## HISTORY

The **getpagesize**() function appeared in 4.2BSD.