VLIMIT(3C) 1989 VLIMIT(3C) NNAAMMEE vlimit - control maximum system resource consumption SSYYNNOOPPSSIISS ##iinncclluuddee <<ssyyss//vvlliimmiitt..hh>> vvlliimmiitt((rreessoouurrccee,, vvaalluuee)) DDEESSCCRRIIPPTTIIOONN TThhiiss iinntteerrffaaccee iiss oobbssoolleetteedd bbyy ggeettrrlliimmiitt((22)).. IItt iiss aavvaaiillaabbllee ffrroomm tthhee ccoommppaattiibbiilliittyy lliibbrraarryy,, lliibbccoommppaatt.. Limits the consumption by the current process and each pro- cess it creates to not individually exceed _v_a_l_u_e on the specified _r_e_s_o_u_r_c_e. If _v_a_l_u_e is specified as -1, then the current limit is returned and the limit is unchanged. The resources which are currently controllable are: LIM_NORAISE A pseudo-limit; if set non-zero then the lim- its may not be raised. Only the super-user may remove the _n_o_r_a_i_s_e 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 _s_b_r_k(2) 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 exceed- ing their declared LIM_MAXRSS. 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; _l_i_m_i_t is thus a built-in command to _c_s_h(1). The system refuses to extend the data or stack space when the limits would be exceeded in the normal way; a _b_r_e_a_k call fails if the data space limit is reached, or the process is killed when the stack limit is reached (since the stack Printed 7/27/90 May 1 VLIMIT(3C) 1989 VLIMIT(3C) 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 nor- mally 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. SSEEEE AALLSSOO csh(1) BBUUGGSS LIM_NORAISE no longer exists. Printed 7/27/90 May 2