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GETRLIMIT(2)		  FreeBSD System Calls Manual		  GETRLIMIT(2)

NAME
     getrlimit,	setrlimit -- control maximum system 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 system resources by the current process and
     each process it creates may be obtained with the getrlimit() call,	and
     set with the setrlimit() call.

     The resource parameter is one of the following:

     RLIMIT_CORE     The largest size (in bytes) core file that	may be cre-
		     ated.

     RLIMIT_CPU	     The maximum amount	of CPU time (in	seconds) to be used by
		     each process.

     RLIMIT_DATA     The maximum size (in bytes) of the	data segment for a
		     process; this includes memory allocated via malloc(3) and
		     all other anonymous memory	mapped via mmap(2).

     RLIMIT_FSIZE    The largest size (in bytes) file that may be created.

     RLIMIT_MEMLOCK  The maximum size (in bytes) which a process may lock into
		     memory using the mlock(2) function.

     RLIMIT_NOFILE   The maximum number	of open	files for this process.

     RLIMIT_NPROC    The maximum number	of simultaneous	processes for this
		     user id.

     RLIMIT_RSS	     The maximum size (in bytes) to which a process's resident
		     set size may grow.	 This setting is no longer enforced,
		     but retained for compatibility.

     RLIMIT_STACK    The maximum size (in bytes) of the	stack segment for a
		     process, which defines how	far a process's	stack segment
		     may be extended.  Stack extension is performed automati-
		     cally by the system, and is only used by the main thread
		     of	a process.

     A resource	limit is specified as a	soft limit and a hard limit.  When a
     soft limit	is exceeded a process may receive a signal (for	example, if
     the CPU time or file size is exceeded), but it will be allowed to con-
     tinue execution until it reaches the hard limit (or modifies its resource
     limit).  The rlimit structure is used to specify the hard and soft	limits
     on	a resource,

	   struct rlimit {
		   rlim_t  rlim_cur;	   /* current (soft) limit */
		   rlim_t  rlim_max;	   /* hard limit */
	   };

     Only the superuser	may raise the maximum limits.  Other users may only
     alter rlim_cur within the range from 0 to rlim_max	or (irreversibly)
     lower rlim_max.

     An	"infinite" value for a limit is	defined	as RLIM_INFINITY.

     A value of	RLIM_SAVED_CUR or RLIM_SAVED_MAX will be stored	in rlim_cur or
     rlim_max respectively by getrlimit() if the value for the current or max-
     imum resource limit cannot	be stored in an	rlim_t.	 The values
     RLIM_SAVED_CUR and	RLIM_SAVED_MAX should not be used in a call to
     setrlimit() unless	they were returned by a	previous call to getrlimit().

     Because this information is stored	in the per-process information,	this
     system call must be executed directly by the shell	if it is to affect all
     future processes created by the shell; limit is thus a built-in command
     to	csh(1) and ulimit is the sh(1) equivalent.

     The system	refuses	to extend the data or stack space when the limits
     would be exceeded in the normal way: a brk(2) call	fails if the data
     space limit is reached.  When the stack limit is reached, the process re-
     ceives a segmentation fault (SIGSEGV); if this signal is not caught by a
     handler using the signal stack, this signal will kill the process.

     A file I/O	operation that would create a file larger than the process'
     soft limit	will cause the write to	fail and a signal SIGXFSZ to be	gener-
     ated; this	normally terminates the	process, but may be caught.  When the
     soft CPU time limit is exceeded, a	signal SIGXCPU is sent to the offend-
     ing process.

RETURN VALUES
     Upon successful completion, the value 0 is	returned; otherwise the
     value -1 is returned and the global variable errno	is set to indicate the
     error.

ERRORS
     getrlimit() and setrlimit() will fail if:

     [EFAULT]		The address specified for rlp is invalid.

     [EINVAL]		An unrecognized	value for resource was specified.

     In	addition, setrlimit() may return the following errors:

     [EINVAL]		The new	rlim_cur is greater than the new rlim_max.

     [EPERM]		The new	rlim_max is greater than the current maximum
			limit value, and the caller is not the superuser.

SEE ALSO
     csh(1), sh(1), quotactl(2), sigaction(2), sigaltstack(2), sysctl(2)

STANDARDS
     The getrlimit() and setrlimit() functions conform to IEEE Std 1003.1-2008
     ("POSIX.1").

     The RLIMIT_MEMLOCK, RLIMIT_NPROC, and RLIMIT_RSS resources	are non-stan-
     dard extensions.

HISTORY
     The getrlimit() and setrlimit() system calls first	appeared in 4.1cBSD.

BUGS
     The RLIMIT_AS resource is missing.

FreeBSD	13.0		       January 12, 2018			  FreeBSD 13.0

NAME | SYNOPSIS | DESCRIPTION | RETURN VALUES | ERRORS | SEE ALSO | STANDARDS | HISTORY | BUGS

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