vlimit(3C) DG/UX 5.4.2 vlimit(3C)
NAME
vlimit - control maximum system resource consumption
SYNOPSIS
#include <sys/vlimit.h>
vlimit(resource, value)
DESCRIPTION
Limits the consumption by the current process and each process it
creates to not individually exceed value on the specified resource.
If value is specified as -1, then the current limit is returned and
the limit is unchanged. The resources which are currently
controllable are:
LIMNORAISE A pseudo-limit; if set non-zero then the limits may
not be raised. Only the super-user may remove the
noraise restriction.
LIMCPU Maximum number of cpu-seconds to be used by each
process
LIMFSIZE Size of the largest single file that can be created
LIMDATA Maximum growth beyond the end of program text of the
data+stack region via sbrk(2)
LIMSTACK Maximum size of the automatically-extended stack
region
LIMCORE Size of the largest core dump that may be created.
LIMMAXRSS Soft limit for the amount of physical memory (in
bytes) to be given to the program. This information
is specified for the system's benefit; if memory is
tight, the system will prefer to take memory from
processes that are exceeding their declared
LIM_MAXRSS.
Because specifications from this call are 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).
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, or the process is killed when the stack limit
is reached (since the stack cannot be extended, there is no way to
send a signal).
A file I/O operation that would violate file-size limits during
creation will cause a signal SIGXFSZ to be generated. This signal
normally terminates the process, but may be caught. When the CPU
time limit is exceeded, a signal SIGXCPU is sent to the offending
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vlimit(3C) DG/UX 5.4.2 vlimit(3C)
process; to allow the process time to handle the signal, it adds five
seconds to the CPU time limit.
SEE ALSO
csh(1).
BUGS
If LIM_NORAISE is set, then no grace should be given when the CPU
time limit is exceeded.
There should be limit and unlimit commands in sh(1) as well as in
csh.
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