1.\" Copyright (c) 2002 Kyle Martin. All rights reserved. 2.\" 3.\" Redistribution and use in source and binary forms, with or without 4.\" modification, are permitted provided that the following conditions 5.\" are met: 6.\" 1. Redistributions of source code must retain the above copyright 7.\" notice, this list of conditions and the following disclaimer. 8.\" 2. Redistributions in binary form must reproduce the above copyright 9.\" notice, this list of conditions and the following disclaimer in the 10.\" documentation and/or other materials provided with the distribution. 11.\" 12.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 13.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 14.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 15.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 16.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 17.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 18.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 19.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 20.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 21.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 22.\" SUCH DAMAGE. 23.\" 24.Dd October 8, 2026 25.Dt ULIMIT 3 26.Os 27.Sh NAME 28.Nm ulimit 29.Nd get and set process limits 30.Sh LIBRARY 31.Lb libc 32.Sh SYNOPSIS 33.In ulimit.h 34.Ft long 35.Fo ulimit 36.Fa "int cmd" 37.Fa "..." 38.Fc 39.Sh DESCRIPTION 40The 41.Fn ulimit 42function will get and set process limits. 43Currently, this is limited to the maximum file size. 44The 45.Fa cmd 46argument is one of the following: 47.Bl -tag -width ".Dv UL_GETFSIZE" 48.It Dv UL_GETFSIZE 49will return the maximum file size of the current process, 50in units of 512-byte blocks. 51.It Dv UL_SETFSIZE 52will attempt to set the maximum file size of the current 53process and its children, using the second argument (expressed as a long). 54.El 55.Sh RETURN VALUES 56.Rv -std 57.Sh ERRORS 58The 59.Fn ulimit 60function will fail if: 61.Bl -tag -width Er 62.It Bq Er EINVAL 63The command specified was invalid. 64.It Bq Er EPERM 65The limit specified to 66.Fn ulimit 67would have raised the maximum limit value, 68and the caller is not the super-user. 69.El 70.Sh SEE ALSO 71.Xr getrlimit 2 72.Sh STANDARDS 73The 74.Fn ulimit 75function conforms to 76.St -p1003.1-2001 . 77.Sh HISTORY 78The 79.Fn ulimit 80function first appeared in 81.Fx 5.0 . 82.Sh BUGS 83The 84.Fn ulimit 85function provides limited precision for 86setting and retrieving process limits. 87If there is a need for greater precision than the 88type 89.Vt long 90provides, the 91.Xr getrlimit 2 92and 93.Xr setrlimit 2 94functions should be considered. 95