SYSCONF(3) BSD Programmer's Manual SYSCONF(3) NNAAMMEE ssyyssccoonnff - get configurable system variables SSYYNNOOPPSSIISS ##iinncclluuddee <<uunniissttdd..hh>> _l_o_n_g ssyyssccoonnff(_i_n_t _n_a_m_e); DDEESSCCRRIIPPTTIIOONN This interface is defined by IEEE Std1003.1-1988 (``POSIX''). A far more complete interface is available using sysctl(3). The ssyyssccoonnff() function provides a method for applications to determine the current value of a configurable system limit or option variable. The _n_a_m_e argument specifies the system variable to be queried. Symbolic con- stants for each name value are found in the include file <unistd.h>. The available values are as follows: _SC_ARG_MAX The maximum bytes of argument to exec(2). _SC_CHILD_MAX The maximum number of simultaneous processes per user id. _SC_CLK_TCK Number of micro-seconds per hz tick. _SC_NGROUPS_MAX The maximum number of supplemental groups. _SC_OPEN_MAX The maximum number of open files per user id. _SC_STREAM_MAX The minimum maximum number of streams that a process may have open at any one time. _SC_TZNAME_MAX The minimum maximum number of types supported for the name of a timezone. _SC_JOB_CONTROL Return 1 if job control is available on this system, otherwise -1. _SC_SAVED_IDS Returns 1 if saved set-group and saved set-user ID is available, otherwise -1. _SC_VERSION The version of ISO/IEC 9945 (POSIX 1003.1) with which the system attempts to comply. _SC_BC_BASE_MAX The maximum ibase/obase values in the bc(1) utility. _SC_BC_DIM_MAX The maximum array size in the bc(1) utility. _SC_BC_SCALE_MAX The maximum scale value in the bc(1) utility. _SC_BC_STRING_MAX The maximum string length in the bc(1) utility. _SC_COLL_WEIGHTS_MAX The maximum number of weights that can be assigned to any entry of the LC_COLLATE order keyword in the locale definition file. _SC_EXPR_NEST_MAX The maximum number of expressions that can be nested within parenthesis by the expr(1) utility. _SC_LINE_MAX The maximum length in bytes of a text-processing utility's input line. _SC_RE_DUP_MAX The maximum number of repeated occurrences of a regular expres- sion permitted when using interval notation. _SC_2_VERSION The version of POSIX 1003.2 with which the system attempts to comply. _SC_2_C_BIND Return 1 if the system's C-language development facilities sup- port the C-Language Bindings Option, otherwise -1. _SC_2_C_DEV Return 1 if the system supports the C-Language Development Utili- ties Option, otherwise -1. _SC_2_CHAR_TERM Return 1 if the system supports at least one terminal type capa- ble of all operations described in POSIX 1003.2, otherwise -1. _SC_2_FORT_DEV Return 1 if the system supports the FORTRAN Development Utilities Option, otherwise -1. _SC_2_FORT_RUN Return 1 if the system supports the FORTRAN Runtime Utilities Op- tion, otherwise -1. _SC_2_LOCALEDEF Return 1 if the system supports the creation of locales, other- wise -1. _SC_2_SW_DEV Return 1 if the system supports the Software Development Utili- ties Option, otherwise -1. _SC_2_UPE Return 1 if the system supports the User Portability Utilities Option, otherwise -1. RREETTUURRNN VVAALLUUEESS If the call to ssyyssccoonnff is not successful, -1 is returned and _e_r_r_n_o is set appropriately. Otherwise, if the variable is associated with funtionali- ty that is not supported, -1 is returned and _e_r_r_n_o is not modified. Oth- erwise, the current variable value is returned. EERRRROORRSS The ssyyssccoonnff() function may fail and set _e_r_r_n_o for any of the errors spec- ified for the library functions sysctl(3). In addition, the following errors may be reported: [EINVAL] The value of the _n_a_m_e argument is invalid. SSEEEE AALLSSOO sysctl(3) BBUUGGSS The value for _SC_STREAM_MAX is a minimum maximum, and required to be the same as ANSI C's FOPEN_MAX, so the returned value is a ridiculously small and misleading number. SSTTAANNDDAARRDDSS The ssyyssccoonnff() function conforms to IEEE Std1003.1-1988 (``POSIX''). HHIISSTTOORRYY The ssyyssccoonnff function first appeared in 4.4BSD. 4th Berkeley Distribution July 12, 1993 3