vlimit(3) Library Functions Manual vlimit(3)
Name
vlimit - control maximum system resource consumption
Syntax
#include <sys/vlimit.h>
vlimit(resource, value)
Description
This facility has been superseded by
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:
LIM_NORAISE Pseudo-limit; if set nonzero then the limits may not be raised. Only the super-user may remove the noraise restriction.
LIM_CPU The maximum number of cpu-seconds to be used by each process.
LIM_FSIZE The largest single file which can be created.
LIM_DATA The maximum growth of the data+stack region via beyond the end of the program text.
LIM_STACK The maximum size of the automatically-extended stack region.
LIM_CORE the size of the largest core dump that will be created.
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 LIM_MAXRSS.
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
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.
Restrictions
If LIM_NORAISE is set, then no grace should be given when the CPU time limit is exceeded.
See Also
csh(1)
vlimit(3)