man3/ulimit.3

.\" Copyright (C) 1996 Andries Brouwer (aeb@cwi.nl)
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.TH ULIMIT 3 2021-03-22 "Linux" "Linux Programmer's Manual"
.SH NAME
ulimit \- get and set user limits
.SH SYNOPSIS
.nf
.B #include <ulimit.h>
.PP
.BI "long ulimit(int " cmd ", long " newlimit );
.fi
.SH DESCRIPTION
Warning: this routine is obsolete.
Use
.BR getrlimit (2),
.BR setrlimit (2),
and
.BR sysconf (3)
instead.
For the shell command
.BR ulimit ,
see
.BR bash (1).
.PP
The
.BR ulimit ()
call will get or set some limit for the calling process.
The
.I cmd
argument can have one of the following values.
.TP
.B UL_GETFSIZE
Return the limit on the size of a file, in units of 512 bytes.
.TP
.B UL_SETFSIZE
Set the limit on the size of a file.
.TP
.B 3
(Not implemented for Linux.)
Return the maximum possible address of the data segment.
.TP
.B 4
(Implemented but no symbolic constant provided.)
Return the maximum number of files that the calling process can open.
.SH RETURN VALUE
On success,
.BR ulimit ()
returns a nonnegative value.
On error, \-1 is returned, and
.I errno
is set to indicate the error.
.SH ERRORS
.TP
.B EPERM
An unprivileged process tried to increase a limit.
.SH ATTRIBUTES
For an explanation of the terms used in this section, see
.BR attributes (7).
.ad l
.nh
.TS
allbox;
lbx lb lb
l l l.
Interface	Attribute	Value
T{
.BR ulimit ()
T}	Thread safety	MT-Safe
.TE
.hy
.ad
.sp 1
.SH CONFORMING TO
SVr4, POSIX.1-2001.
POSIX.1-2008 marks
.BR ulimit ()
as obsolete.
.SH SEE ALSO
.BR bash (1),
.BR getrlimit (2),
.BR setrlimit (2),
.BR sysconf (3)