ULIMIT(2)ULIMIT(2)NAMEulimit - get and set process limits
SYNOPSIS
#include <ulimit.h>
long ulimit(int cmd, /* newlimit */...);
DESCRIPTION
The ulimit() function provides for control over process limits. It is
effective in limiting the growth of regular files. Pipes are limited to
PIPE_MAX bytes.
The cmd values, defined in <ulimit.h>, include:
UL_GETFSIZE
Return the soft file size limit of the process. The
limit is in units of 512-byte blocks and is inherited by
child processes. Files of any size can be read. The
return value is the integer part of the soft file size
limit divided by 512. If the result cannot be repre‐
sented as a long int, the result is unspecified.
UL_SETFSIZE
Set the hard and soft file size limits for output opera‐
tions of the process to the value of the second argu‐
ment, taken as a long int. Any process may decrease its
own hard limit, but only a process with appropriate
privileges may increase the limit. The new file size
limit is returned. The hard and soft file size limits
are set to the specified value multiplied by 512. If
the result would overflow an rlimit_t, the actual value
set is unspecified.
UL_GMEMLIM
Get the maximum possible break value (see brk(2)).
UL_GDESLIM
Get the current value of the maximum number of open
files per process configured in the system.
RETURN VALUES
Upon successful completion, ulimit() returns the value of the requested
limit. Otherwise, −1 is returned, the limit is not changed, and errno
is set to indicate the error.
ERRORS
The ulimit() function will fail if:
EINVAL
The cmd argument is not valid.
EPERM
A process that has not asserted {PRIV_SYS_RESOURCE} in its
effective set is trying to increase its file size limit.
USAGE
Since all return values are permissible in a successful situation, an
application wishing to check for error situations should set errno to
0, then call ulimit(), and if it returns −1, check if errno is non-
zero.
The getrlimit() and setrlimit() functions provide a more general inter‐
face for controlling process limits, and are preferred over ulimit().
See getrlimit(2).
ATTRIBUTES
See attributes(5) for descriptions of the following attributes:
┌────────────────────┬─────────────────┐
│ ATTRIBUTE TYPE │ ATTRIBUTE VALUE │
├────────────────────┼─────────────────┤
│Interface Stability │ Standard │
└────────────────────┴─────────────────┘
SEE ALSObrk(2), getrlimit(2), write(2), attributes(5), privileges(5), stan‐
dards(5)
Feb 1, 2003 ULIMIT(2)
