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ulimit(3) — Linux manual page

ulimit(3) Library Functions Manual ulimit(3)

NAME top

 ulimit - get and set user limits

LIBRARY top

 Standard C library (libc, -lc)

SYNOPSIS top

 #include <ulimit.h>
 [[deprecated]] long ulimit(int cmd, long newlimit);

DESCRIPTION top

 Warning: this routine is obsolete.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 top

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

ERRORS top

 EPERM An unprivileged process tried to increase a limit.

ATTRIBUTES top

 For an explanation of the terms used in this section, see
 attributes(7).
 ┌──────────────────────────────────────┬───────────────┬─────────┐
 │ Interface │ Attribute │ Value │
 ├──────────────────────────────────────┼───────────────┼─────────┤
 │ ulimit() │ Thread safety │ MT-Safe │
 └──────────────────────────────────────┴───────────────┴─────────┘

STANDARDS top

 POSIX.1-2008.

HISTORY top

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

SEE ALSO top

 bash(1), getrlimit(2), setrlimit(2), sysconf(3)

COLOPHON top

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 user-space interface documentation) project. Information about
 the project can be found at 
 ⟨https://www.kernel.org/doc/man-pages/⟩. If you have a bug report
 for this manual page, see
 ⟨https://git.kernel.org/pub/scm/docs/man-pages/man-pages.git/tree/CONTRIBUTING⟩.
 This page was obtained from the tarball man-pages-6.15.tar.gz
 fetched from
 ⟨https://mirrors.edge.kernel.org/pub/linux/docs/man-pages/⟩ on
 2025年08月11日. If you discover any rendering problems in this HTML
 version of the page, or you believe there is a better or more up-
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 man-pages@man7.org
Linux man-pages 6.15 2025年05月17日 ulimit(3)

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Pages that refer to this page: getrlimit(2), syscalls(2), unimplemented(2), lttng-relayd(8)

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