ULIMIT(P) POSIX Programmer's Manual ULIMIT(P)NAMEulimit - get and set process limits
SYNOPSIS
#include <ulimit.h>
long ulimit(int cmd, ...);
DESCRIPTION
The ulimit() function shall control process limits. The process limits
that can be controlled by this function include the maximum size of a
single file that can be written (this is equivalent to using setr‐
limit() with RLIMIT_FSIZE). The cmd values, defined in <ulimit.h>,
include:
UL_GETFSIZE
Return the file size limit (RLIMIT_FSIZE) of the process. The
limit shall be in units of 512-byte blocks and shall be inher‐
ited by child processes. Files of any size can be read. The
return value shall be the integer part of the soft file size
limit divided by 512. If the result cannot be represented as a
long, the result is unspecified.
UL_SETFSIZE
Set the file size limit for output operations of the process to
the value of the second argument, taken as a long, multiplied by
512. If the result would overflow an rlim_t, the actual value
set is unspecified. Any process may decrease its own limit, but
only a process with appropriate privileges may increase the
limit. The return value shall be the integer part of the new
file size limit divided by 512.
The ulimit() function shall not change the setting of errno if success‐
ful.
As 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 to see if errno is
non-zero.
RETURN VALUE
Upon successful completion, ulimit() shall return the value of the
requested limit. Otherwise, -1 shall be returned and errno set to indi‐
cate the error.
ERRORS
The ulimit() function shall fail and the limit shall be unchanged if:
EINVAL The cmd argument is not valid.
EPERM A process not having appropriate privileges attempts to increase
its file size limit.
The following sections are informative.
EXAMPLES
None.
APPLICATION USAGE
None.
RATIONALE
None.
FUTURE DIRECTIONS
None.
SEE ALSOgetrlimit() , setrlimit() , write() , the Base Definitions volume of
IEEE Std 1003.1-2001, <ulimit.h>
COPYRIGHT
Portions of this text are reprinted and reproduced in electronic form
from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology
-- Portable Operating System Interface (POSIX), The Open Group Base
Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of
Electrical and Electronics Engineers, Inc and The Open Group. In the
event of any discrepancy between this version and the original IEEE and
The Open Group Standard, the original IEEE and The Open Group Standard
is the referee document. The original Standard can be obtained online
at http://www.opengroup.org/unix/online.html .
IEEE/The Open Group 2003 ULIMIT(P)
