HP-UX Reference (11i v1 05/09) - 2 System Calls (vol 5)

g
getrlimit(2) getrlimit(2)
NAME
getrlimit(), setrlimit() - control maximum resource consumption
SYNOPSIS
#include <sys/resource.h>
int getrlimit(int resource, struct rlimit *rlp);
int setrlimit(int resource, const struct rlimit *rlp);
DESCRIPTION
Limits on the consumption of a variety of resources by the calling process may be obtained with
getrlimit() and set with setrlimit() . Each call to either
getrlimit() or setrlimit()
identifies a specific resource to be operated upon as well as a resource limit. A resource limit is represented
by an rlimit structure, pointed to by the rlp argument and includes the following members:
rlim_t rlim_cur; /* Current (soft) limit */
rlim_t rlim_max; /* Hard limit */
The
rlim_cur member specifies the current or soft limit and the rlim_max member specifies the max-
imum or hard limit. Soft limits may be changed by a process to any value that is less than or equal to the
hard limit. A process may (irreversibly) lower its hard limit to any value that is greater than or equal to
the soft limit. Only a process with appropriate privileges can raise a hard limit. Both hard and soft limits
can be changed in a single call to setrlimit() subject to the constraints described above.
The value RLIM_INFINITY, defined in <
sys/resource.h>, is considered to be larger than any other
limit value. If a call to
getrlimit() returns RLIM_INFINITY
for a resource, it means the implemen-
tation does not enforce limits on that resource. Specifying
RLIM_INFINITY
as any resource limit value
on a successful call to
setrlimit() inhibits enforcement of that resource limit.
The following resources are defined:
RLIMIT_CORE This is the maximum size of a core file in bytes that may be created by a
process. A limit of 0 will prevent the creation of a core file. If this limit is
exceeded, the writing of a core file will terminate at this size.
RLIMIT_CPU This is the maximum amount of CPU time in seconds allowed for a UNIX
95 conforming application. If this limit is exceeded, SIGXCPU is generated
for the application. The default action for a UNIX 95 conforming applica-
tion is to kill the process and leave a core file. If the process is blocking,
catching or ignoring SIGXCPU, the behavior is unspecified. If the applica-
tion is a Classic HP-UX application, the kernel will not send the signal as a
result of exceeding the CPU limit. However, if this signal is sent explicitly
to a Classic HP-UX application by another application or via the kill
-XCPU
command, this signal will be delivered and the default action will
be taken. In order for an application to be UNIX 95, it must be linked with
unix95.o either directly or indirectly. For example:
% cc /usr/lib/unix95.o prog.c
Or,
% export UNIX95=1
% cc prog.c
RLIMIT_DATA
This is the maximum size of a process’ data segment in bytes. If this limit
is exceeded, the brk(), malloc(), and sbrk() functions will fail with
errno set to [ENOMEM].
RLIMIT_FSIZE This option is only applicable to UNIX 95 conforming applications. Please
see RLIMIT_CPU option above for explanation on UNIX 95 conforming
applications. This is the maximum size of a file in bytes that may be
created by a process. A limit of 0 will prevent the creation of a file. If a
write or truncate operation would cause this limit to be exceeded,
SIGXFSZ is generated for the process. If the process is blocking, catching
or ignoring SIGXFSZ, continued attempts to increase the size of a file
from end-of-file to beyond the limit will fail with errno set to [EFBIG].
HP-UX 11i Version 1: September 2005 − 1 − Hewlett-Packard Company Section 2−−109