ulimit(3)

ulimit3

Get and set user limits

Usage

#include <ulimit.h>

[[deprecated]] long ulimit(int cmd, long newlimit);

Library

Standard C library (libc, -lc)

Overview

Warning: this routine is obsolete. Use getrlimit(2), setrlimit(2), and sysconf(3) instead. For the shell command ulimit, see bash(1).

The ulimit() call will get or set some limit for the calling process. The cmd argument can have one of the following values.

UL_GETFSIZE

Return the limit on the size of a file, in units of 512 bytes.

UL_SETFSIZE

Set the limit on the size of a file.

3

(Not implemented for Linux.) Return the maximum possible address of the data segment.

4

(Implemented but no symbolic constant provided.) Return the maximum number of files that the calling process can open.

Return value

On success, ulimit() returns a nonnegative value. On error, -1 is returned, and errno is set to indicate the error.

Errors

EPERM

An unprivileged process tried to increase a limit.

Attributes

For an explanation of the terms used in this section, see attributes(7).

InterfaceAttributeValue
ulimit()Thread safetyMT-Safe

Releases

15 releases since Debian 2.1 (Slink); the text changed 13 times.

  1. 2.1–2.2
  2. 3.0
  3. 3.1
  4. 4.0
  5. 5.0
  6. 6.0
  7. 7
  8. 8
  9. 9
  10. 10
  11. 11
  12. 12
  13. 13
  14. Arch

Standards

POSIX.1-2008.

History

SVr4, POSIX.1-2001. POSIX.1-2008 marks it as obsolete.

From man-pages 6.19-1 in Arch Linux 2026-11-01. Parsed by carta from the page's man source.