---
name: "getdtablesize"
section: "2"
platform: "macos"
package: "xnu"
version: "12377.121.6"
release: "macOS 26.5"
platforms: ["linux", "freebsd", "macos"]
url: "https://new.carta.tech/getdtablesize"
---

# getdtablesize(2)

get descriptor table size

## NAME

**getdtablesize** – get descriptor table size

## LIBRARY

Standard C Library (libc, -lc)

## SYNOPSIS

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

*int*\

**getdtablesize**(*void*);

## DESCRIPTION

Each process has a fixed size descriptor table, which is guaranteed to have at least 20 slots.  The entries in the descriptor table are numbered with small integers starting at 0. The call **getdtablesize**() returns the size of this table.

## LEGACY

The [getrlimit(2)](/getrlimit/2.md) function returns a value of type  *rlim\_t*. This interface, returning an  *int*, may have problems representing appropriate values in the future. Applications should use the  [getrlimit(2)](/getrlimit/2.md) function instead.

## SEE ALSO

[close(2)](/close/2.md), [dup(2)](/dup/2.md), [getrlimit(2)](/getrlimit/2.md), [open(2)](/open/2.md), [select(2)](/select/2.md)

## HISTORY

The **getdtablesize**() function call appeared in 4.2BSD.