| GETRLIMIT(2) | System Calls Manual | GETRLIMIT(2) | 
getrlimit, setrlimit —
#include <sys/resource.h>
int
  
  getrlimit(int
    resource, struct rlimit
    *rlp);
int
  
  setrlimit(int
    resource, const struct
    rlimit *rlp);
getrlimit() call, and set with the
  setrlimit() call. Resources of an arbitrary process
  can be obtained/changed using
  sysctl(3).
The resource parameter is one of the following:
RLIMIT_ASRLIMIT_CORERLIMIT_CPURLIMIT_DATARLIMIT_FSIZERLIMIT_MEMLOCKRLIMIT_NOFILERLIMIT_NPROCRLIMIT_NTHRRLIMIT_RSSRLIMIT_SBSIZESO_RCVBUF and SO_SNDBUF
      options.RLIMIT_STACKA 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 continue 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 super-user 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.
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. Thus, shells provide built-in
    commands to change the limits (limit for
    csh(1), or
    ulimit for
    sh(1)).
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
    receives 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 that the
    process' soft limit will cause the write to fail and a signal
    SIGXFSZ to be generated; this normally terminates
    the process, but may be caught. When the soft CPU time limit is exceeded, a
    signal SIGXCPU is sent to the offending process.
getrlimit() and setrlimit()
  will fail if:
EFAULT]EINVAL]setrlimit() call, the specified
      rlim_cur exceeds the specified
      rlim_max.EPERM]setrlimit() would have
      raised the maximum limit value, and the caller is not the super-user.The setrlimit() function may fail if:
EINVAL]setrlimit() cannot be
      lowered, because current usage is already higher than the limit.getrlimit() function call appeared in
  4.2BSD.
RLIMIT_RSS is not implemented in
  uvm(9) which means that process
  memory size limits are not enforced.
| June 8, 2012 | NetBSD 10.0 |