vlimit - control maximum system resource consumption
This facility is superseded by getrlimit(2)*.
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
LIM_NORAISE A pseudo-limit; if
set non-zero then the limits may
not be raised. Only the super-user may remove the
LIM_CPU the maximum number of
cpu-seconds to be used by each
LIM_FSIZE the largest single file which can be created
LIM_DATA the maximum growth of
the data+stack region via
sbrk(2) beyond the end of the program text
LIM_STACK the maximum size of
the automatically-extended stack
LIM_CORE the size of the largest
core dump that will be
LIM_MAXRSS a soft limit for the
amount of physical memory (in
bytes) to be given to the program. If memory is
tight, the system will prefer to take memory from
processes which are exceeding their declared
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).
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 which would
create a file which is too large
will cause a signal SIGXFSZ to be generated, this normally
terminates the process, but may be caught. When the cpu time limit
is exceeded, a signal SIGXCPU is sent to the offending process; to
allow it time to process the signal it is given 5 seconds grace by
raising the cpu time limit.
LIM_NORAISE no longer exists.
* Not currently supported under MachTen Personal Unix