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Annotation of researchv10dc/man/manb/vlimit.2v, revision 1.1.1.1

1.1       root        1: .TH VLIMIT 2V
                      2: .UC 4
                      3: .SH NAME
                      4: vlimit \- control maximum system resource consumption
                      5: .SH SYNOPSIS
                      6: .B "#include <sys/vlimit.h>"
                      7: .PP
                      8: .B vlimit(resource, value)
                      9: .SH DESCRIPTION
                     10: Limits the consumption by the current process and each process
                     11: it creates to not individually exceed 
                     12: .I value
                     13: on the specified
                     14: .I resource.
                     15: If
                     16: .I value
                     17: is specified as \-1, then the current limit is returned and the
                     18: limit is unchanged.
                     19: The resources which are currently controllable are:
                     20: .TP 15
                     21: .B LIM_NORAISE
                     22: A pseudo-limit; if set non-zero then the limits may not be raised.
                     23: Only the super-user may remove the \fInoraise\fR restriction.
                     24: .TP 15
                     25: .B LIM_CPU
                     26: the maximum
                     27: number of cpu-seconds to be used by each process
                     28: .TP 15
                     29: .B LIM_FSIZE
                     30: the largest single file which can be created
                     31: .TP 15
                     32: .B LIM_DATA
                     33: the maximum growth of the data+stack region via
                     34: .IR sbrk (2)
                     35: beyond the end of the program text
                     36: .TP 15
                     37: .B LIM_STACK
                     38: the maximum
                     39: size of the automatically-extended stack region
                     40: .TP 15
                     41: .B LIM_CORE
                     42: the size of the largest core dump that will be created.
                     43: .PP
                     44: Because this information is stored in the per-process information
                     45: this system call must be executed directly by the shell if it
                     46: is to affect all future processes created by the shell;
                     47: .I limit
                     48: is thus a built-in command to
                     49: .IR csh (1).
                     50: .PP
                     51: The system refuses to extend the data or stack space when the limits
                     52: would be exceeded in the normal way; a
                     53: .I break
                     54: call fails if the data space limit is reached, or the process is
                     55: killed when the stack limit is reaches (since the stack cannot be
                     56: extended, there is no way to send a signal!).
                     57: .PP
                     58: A file i/o operation which would create a file which is too large
                     59: will cause a signal SIGXFSZ to be generated, this normally terminates
                     60: the process, but may be caught.
                     61: When the cpu time limit is exceeded, a signal SIGXCPU is sent to the
                     62: offending process; to allow it time to process the signal it is
                     63: given 5 seconds grace by raising the cpu time limit.
                     64: .SH SEE ALSO
                     65: csh(1)
                     66: .SH BUGS
                     67: If LIM_NORAISE is set, then no grace should be given when the cpu
                     68: time limit is exceeded.
                     69: .PP
                     70: There should be 
                     71: .I limit
                     72: and
                     73: .I unlimit
                     74: commands in
                     75: .IR sh (1)
                     76: as well as in
                     77: .IR csh.
                     78: .PP
                     79: This call is peculiar to this version of UNIX.
                     80: The options and specifications of this system call and even the call itself
                     81: are subject to change.  It may be extended or replaced by other
                     82: facilities in future versions of the system.

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