sysconf(3) Library Functions Manual sysconf(3) sysconf - (libc -lc) #include long sysconf(int name); POSIX . / . sysconf(). fpathconf(3) pathconf(3). confstr(3). . . _POSIX_FOO . . -1 . 0 . -1 0 . ( 200112L) POSIX . glibc 1 POSIX . sysconf() _SC_FOO. posixoptions(7). _FOO _POSIX_FOO . . . sysconf(). sysconf() _SC_FOO. POSIX.1 sysconf() . POSIX.1. ARG_MAX - _SC_ARG_MAX exec(3). _POSIX_ARG_MAX (4096). CHILD_MAX - _SC_CHILD_MAX . _POSIX_CHILD_MAX (25). HOST_NAME_MAX - _SC_HOST_NAME_MAX gethostname(2). _POSIX_HOST_NAME_MAX (255). LOGIN_NAME_MAX - _SC_LOGIN_NAME_MAX . _POSIX_LOGIN_NAME_MAX (9). NGROUPS_MAX - _SC_NGROUPS_MAX . - _SC_CLK_TCK . . CLK_TCK. (: CLOCKS_PER_SEC : 1000000.) OPEN_MAX - _SC_OPEN_MAX . _POSIX_OPEN_MAX (20). PAGESIZE - _SC_PAGESIZE . 1. PAGE_SIZE - _SC_PAGE_SIZE PAGESIZE/_SC_PAGESIZE. ( PAGESIZE PAGE_SIZE POSIX.) RE_DUP_MAX - _SC_RE_DUP_MAX BRE regexec(3) regcomp(3). _POSIX2_RE_DUP_MAX (255). STREAM_MAX - _SC_STREAM_MAX . C FOPEN_MAX. _POSIX_STREAM_MAX (8). SYMLOOP_MAX - _SC_SYMLOOP_MAX ELOOP. _POSIX_SYMLOOP_MAX (8). TTY_NAME_MAX - _SC_TTY_NAME_MAX . _POSIX_TTY_NAME_MAX (9). TZNAME_MAX - _SC_TZNAME_MAX . _POSIX_TZNAME_MAX (6). _POSIX_VERSION - _SC_VERSION POSIX.1 YYYYMML 199009L 1990. POSIX.2 POSIX.2 . BC_BASE_MAX - _SC_BC_BASE_MAX obase bc(1). BC_DIM_MAX - _SC_BC_DIM_MAX bc(1). BC_SCALE_MAX - _SC_BC_SCALE_MAX scale bc(1). BC_STRING_MAX - _SC_BC_STRING_MAX bc(1). COLL_WEIGHTS_MAX - _SC_COLL_WEIGHTS_MAX LC_COLLATE order . EXPR_NEST_MAX - _SC_EXPR_NEST_MAX expr(1). LINE_MAX - _SC_LINE_MAX . . RE_DUP_MAX - _SC_RE_DUP_MAX \{m,n\}. POSIX2_VERSION - _SC_2_VERSION POSIX.2 YYYYMML. POSIX2_C_DEV - _SC_2_C_DEV C POSIX.2 . POSIX2_FORT_DEV - _SC_2_FORT_DEV FORTRAN POSIX.2 . POSIX2_FORT_RUN - _SC_2_FORT_RUN FORTRAN POSIX.2 . _POSIX2_LOCALEDEF - _SC_2_LOCALEDEF POSIX.2 localedef(1) . POSIX2_SW_DEV - _SC_2_SW_DEV POSIX.2 . . - _SC_PHYS_PAGES . _SC_PAGESIZE. - _SC_AVPHYS_PAGES . - _SC_NPROCESSORS_CONF . get_nprocs_conf(3). - _SC_NPROCESSORS_ONLN (). get_nprocs_conf(3). sysconf() : o -1 errno ( EINVAL name ). o name -1 errno. ( errno errno -1). o name -1 . o . . EINVAL name . attributes(7). +----------------------+------------------------------------+------------------------------------------------------------------------+ | | | | +----------------------+------------------------------------+------------------------------------------------------------------------+ |sysconf() | | (MT-Safe) | +----------------------+------------------------------------+------------------------------------------------------------------------+ POSIX.1-2008. POSIX.1-2001. ARG_MAX exec(3) . . bc(1) expr(1) getconf(1) locale(1) confstr(3) fpathconf(3) pathconf(3) posixoptions(7) 3 . . : . 6.18 8 2026 sysconf(3)