GETRLIMIT(2-BSD)    RISC/os Reference Manual     GETRLIMIT(2-BSD)



NAME
     getrlimit, setrlimit - control maximum system resource con-
     sumption

SYNOPSIS
     #include <sys/time.h>
     #include <sys/resource.h>

     getrlimit(resource, rlp)
     int resource;
     struct rlimit *rlp;

     setrlimit(resource, rlp)
     int resource;
     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_CPU
               the maximum amount of cpu time (in seconds) to be
               used by each process.

     RLIMIT_FSIZE
               the largest size, in bytes, of any single file
               that may be created.

     RLIMIT_DATA
               the maximum size, in bytes, of the data segment
               for a process; this defines how far a program may
               extend its break with the sbrk see brk(2) system
               call.

     RLIMIT_STACK
               the maximum size, in bytes, of the stack segment
               for a process; this defines how far a program's
               stack segment may be extended.  Stack extension is
               performed automatically by the system.

     RLIMIT_CORE
               the largest size, in bytes, of a core file that
               may be created.

     RLIMIT_RSS
               the maximum size, in bytes, to which a process's
               resident set size may grow.  This imposes a limit
               on the amount of physical memory to be given to a
               process; if memory is tight, the system will



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               prefer to take memory from processes that are
               exceeding their declared resident set size.

     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 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 {
               int  rlim_cur; /* current (soft) limit */
               int  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
     (0x7fffffff).

     Because this information is stored in the per-process infor-
     mation, 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).

     The system refuses to extend the data or stack space when
     the limits would be exceeded in the normal way: a break 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 that is too
     large will cause a signal SIGXFSZ to be generated; this nor-
     mally terminates the process, but may be caught.  When the
     soft cpu time limit is exceeded, a signal SIGXCPU is sent to
     the offending process.

RETURN VALUE
     A 0 return value indicates that the call succeeded, changing
     or returning the resource limit.   A return value of -1
     indicates that an error occurred, and an error code is
     stored in the global location errno.

ERRORS
     The possible errors are:

     [EFAULT]
          The address specified for rlp is invalid.



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     [EPERM]
          The limit specified to setrlimit would have raised the
          maximum limit value, and the caller is not the super-
          user.

SEE ALSO
     quota(2), sigvec(2), sigstack(2).
     csh(1) in the User's Reference Manual.

WARNINGS
     There should be limit and unlimit commands in sh(1) as well
     as in csh.











































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