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-
- SYSCONF(3) UNIX 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 functional-
- ity that is not supported, -1 is returned and _e_r_r_n_o is not modified.
- Otherwise, 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
- error 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 April 19, 1994 3
-