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31.4.2 Constants for sysconf Parameters

Here are the symbolic constants for use as the parameter argument to sysconf. The values are all integer constants (more specifically, enumeration type values).

_SC_ARG_MAX
Inquire about the parameter corresponding to ARG_MAX.
_SC_CHILD_MAX
Inquire about the parameter corresponding to CHILD_MAX.
_SC_OPEN_MAX
Inquire about the parameter corresponding to OPEN_MAX.
_SC_STREAM_MAX
Inquire about the parameter corresponding to STREAM_MAX.
_SC_TZNAME_MAX
Inquire about the parameter corresponding to TZNAME_MAX.
_SC_NGROUPS_MAX
Inquire about the parameter corresponding to NGROUPS_MAX.
_SC_JOB_CONTROL
Inquire about the parameter corresponding to _POSIX_JOB_CONTROL.
_SC_SAVED_IDS
Inquire about the parameter corresponding to _POSIX_SAVED_IDS.
_SC_VERSION
Inquire about the parameter corresponding to _POSIX_VERSION.
_SC_CLK_TCK
Inquire about the parameter corresponding to CLOCKS_PER_SEC; see CPU Time.
_SC_CHARCLASS_NAME_MAX
Inquire about the parameter corresponding to maximal length allowed for a character class name in an extended locale specification. These extensions are not yet standardized and so this option is not standardized as well.
_SC_REALTIME_SIGNALS
Inquire about the parameter corresponding to _POSIX_REALTIME_SIGNALS.
_SC_PRIORITY_SCHEDULING
Inquire about the parameter corresponding to _POSIX_PRIORITY_SCHEDULING.
_SC_TIMERS
Inquire about the parameter corresponding to _POSIX_TIMERS.
_SC_ASYNCHRONOUS_IO
Inquire about the parameter corresponding to _POSIX_ASYNCHRONOUS_IO.
_SC_PRIORITIZED_IO
Inquire about the parameter corresponding to _POSIX_PRIORITIZED_IO.
_SC_SYNCHRONIZED_IO
Inquire about the parameter corresponding to _POSIX_SYNCHRONIZED_IO.
_SC_FSYNC
Inquire about the parameter corresponding to _POSIX_FSYNC.
_SC_MAPPED_FILES
Inquire about the parameter corresponding to _POSIX_MAPPED_FILES.
_SC_MEMLOCK
Inquire about the parameter corresponding to _POSIX_MEMLOCK.
_SC_MEMLOCK_RANGE
Inquire about the parameter corresponding to _POSIX_MEMLOCK_RANGE.
_SC_MEMORY_PROTECTION
Inquire about the parameter corresponding to _POSIX_MEMORY_PROTECTION.
_SC_MESSAGE_PASSING
Inquire about the parameter corresponding to _POSIX_MESSAGE_PASSING.
_SC_SEMAPHORES
Inquire about the parameter corresponding to _POSIX_SEMAPHORES.
_SC_SHARED_MEMORY_OBJECTS
Inquire about the parameter corresponding to
_POSIX_SHARED_MEMORY_OBJECTS.
_SC_AIO_LISTIO_MAX
Inquire about the parameter corresponding to _POSIX_AIO_LISTIO_MAX.
_SC_AIO_MAX
Inquire about the parameter corresponding to _POSIX_AIO_MAX.
_SC_AIO_PRIO_DELTA_MAX
Inquire the value by which a process can decrease its asynchronous I/O priority level from its own scheduling priority. This corresponds to the run-time invariant value AIO_PRIO_DELTA_MAX.
_SC_DELAYTIMER_MAX
Inquire about the parameter corresponding to _POSIX_DELAYTIMER_MAX.
_SC_MQ_OPEN_MAX
Inquire about the parameter corresponding to _POSIX_MQ_OPEN_MAX.
_SC_MQ_PRIO_MAX
Inquire about the parameter corresponding to _POSIX_MQ_PRIO_MAX.
_SC_RTSIG_MAX
Inquire about the parameter corresponding to _POSIX_RTSIG_MAX.
_SC_SEM_NSEMS_MAX
Inquire about the parameter corresponding to _POSIX_SEM_NSEMS_MAX.
_SC_SEM_VALUE_MAX
Inquire about the parameter corresponding to _POSIX_SEM_VALUE_MAX.
_SC_SIGQUEUE_MAX
Inquire about the parameter corresponding to _POSIX_SIGQUEUE_MAX.
_SC_TIMER_MAX
Inquire about the parameter corresponding to _POSIX_TIMER_MAX.
_SC_PII
Inquire about the parameter corresponding to _POSIX_PII.
_SC_PII_XTI
Inquire about the parameter corresponding to _POSIX_PII_XTI.
_SC_PII_SOCKET
Inquire about the parameter corresponding to _POSIX_PII_SOCKET.
_SC_PII_INTERNET
Inquire about the parameter corresponding to _POSIX_PII_INTERNET.
_SC_PII_OSI
Inquire about the parameter corresponding to _POSIX_PII_OSI.
_SC_SELECT
Inquire about the parameter corresponding to _POSIX_SELECT.
_SC_UIO_MAXIOV
Inquire about the parameter corresponding to _POSIX_UIO_MAXIOV.
_SC_PII_INTERNET_STREAM
Inquire about the parameter corresponding to _POSIX_PII_INTERNET_STREAM.
_SC_PII_INTERNET_DGRAM
Inquire about the parameter corresponding to _POSIX_PII_INTERNET_DGRAM.
_SC_PII_OSI_COTS
Inquire about the parameter corresponding to _POSIX_PII_OSI_COTS.
_SC_PII_OSI_CLTS
Inquire about the parameter corresponding to _POSIX_PII_OSI_CLTS.
_SC_PII_OSI_M
Inquire about the parameter corresponding to _POSIX_PII_OSI_M.
_SC_T_IOV_MAX
Inquire the value of the value associated with the T_IOV_MAX variable.
_SC_THREADS
Inquire about the parameter corresponding to _POSIX_THREADS.
_SC_THREAD_SAFE_FUNCTIONS
Inquire about the parameter corresponding to
_POSIX_THREAD_SAFE_FUNCTIONS.
_SC_GETGR_R_SIZE_MAX
Inquire about the parameter corresponding to _POSIX_GETGR_R_SIZE_MAX.
_SC_GETPW_R_SIZE_MAX
Inquire about the parameter corresponding to _POSIX_GETPW_R_SIZE_MAX.
_SC_LOGIN_NAME_MAX
Inquire about the parameter corresponding to _POSIX_LOGIN_NAME_MAX.
_SC_TTY_NAME_MAX
Inquire about the parameter corresponding to _POSIX_TTY_NAME_MAX.
_SC_THREAD_DESTRUCTOR_ITERATIONS
Inquire about the parameter corresponding to _POSIX_THREAD_DESTRUCTOR_ITERATIONS.
_SC_THREAD_KEYS_MAX
Inquire about the parameter corresponding to _POSIX_THREAD_KEYS_MAX.
_SC_THREAD_STACK_MIN
Inquire about the parameter corresponding to _POSIX_THREAD_STACK_MIN.
_SC_THREAD_THREADS_MAX
Inquire about the parameter corresponding to _POSIX_THREAD_THREADS_MAX.
_SC_THREAD_ATTR_STACKADDR
Inquire about the parameter corresponding to
a _POSIX_THREAD_ATTR_STACKADDR.
_SC_THREAD_ATTR_STACKSIZE
Inquire about the parameter corresponding to
_POSIX_THREAD_ATTR_STACKSIZE.
_SC_THREAD_PRIORITY_SCHEDULING
Inquire about the parameter corresponding to _POSIX_THREAD_PRIORITY_SCHEDULING.
_SC_THREAD_PRIO_INHERIT
Inquire about the parameter corresponding to _POSIX_THREAD_PRIO_INHERIT.
_SC_THREAD_PRIO_PROTECT
Inquire about the parameter corresponding to _POSIX_THREAD_PRIO_PROTECT.
_SC_THREAD_PROCESS_SHARED
Inquire about the parameter corresponding to _POSIX_THREAD_PROCESS_SHARED.
_SC_2_C_DEV
Inquire about whether the system has the POSIX.2 C compiler command, c89.
_SC_2_FORT_DEV
Inquire about whether the system has the POSIX.2 Fortran compiler command, fort77.
_SC_2_FORT_RUN
Inquire about whether the system has the POSIX.2 asa command to interpret Fortran carriage control.
_SC_2_LOCALEDEF
Inquire about whether the system has the POSIX.2 localedef command.
_SC_2_SW_DEV
Inquire about whether the system has the POSIX.2 commands ar, make, and strip.
_SC_BC_BASE_MAX
Inquire about the maximum value of obase in the bc utility.
_SC_BC_DIM_MAX
Inquire about the maximum size of an array in the bc utility.
_SC_BC_SCALE_MAX
Inquire about the maximum value of scale in the bc utility.
_SC_BC_STRING_MAX
Inquire about the maximum size of a string constant in the bc utility.
_SC_COLL_WEIGHTS_MAX
Inquire about the maximum number of weights that can necessarily be used in defining the collating sequence for a locale.
_SC_EXPR_NEST_MAX
Inquire about the maximum number of expressions nested within parentheses when using the expr utility.
_SC_LINE_MAX
Inquire about the maximum size of a text line that the POSIX.2 text utilities can handle.
_SC_EQUIV_CLASS_MAX
Inquire about the maximum number of weights that can be assigned to an entry of the LC_COLLATE category ‘order’ keyword in a locale definition. The GNU C library does not presently support locale definitions.
_SC_VERSION
Inquire about the version number of POSIX.1 that the library and kernel support.
_SC_2_VERSION
Inquire about the version number of POSIX.2 that the system utilities support.
_SC_PAGESIZE
Inquire about the virtual memory page size of the machine. getpagesize returns the same value (see Query Memory Parameters).
_SC_NPROCESSORS_CONF
Inquire about the number of configured processors.
_SC_NPROCESSORS_ONLN
Inquire about the number of processors online.
_SC_PHYS_PAGES
Inquire about the number of physical pages in the system.
_SC_AVPHYS_PAGES
Inquire about the number of available physical pages in the system.
_SC_ATEXIT_MAX
Inquire about the number of functions which can be registered as termination functions for atexit; see Cleanups on Exit.
_SC_XOPEN_VERSION
Inquire about the parameter corresponding to _XOPEN_VERSION.
_SC_XOPEN_XCU_VERSION
Inquire about the parameter corresponding to _XOPEN_XCU_VERSION.
_SC_XOPEN_UNIX
Inquire about the parameter corresponding to _XOPEN_UNIX.
_SC_XOPEN_REALTIME
Inquire about the parameter corresponding to _XOPEN_REALTIME.
_SC_XOPEN_REALTIME_THREADS
Inquire about the parameter corresponding to _XOPEN_REALTIME_THREADS.
_SC_XOPEN_LEGACY
Inquire about the parameter corresponding to _XOPEN_LEGACY.
_SC_XOPEN_CRYPT
Inquire about the parameter corresponding to _XOPEN_CRYPT.
_SC_XOPEN_ENH_I18N
Inquire about the parameter corresponding to _XOPEN_ENH_I18N.
_SC_XOPEN_SHM
Inquire about the parameter corresponding to _XOPEN_SHM.
_SC_XOPEN_XPG2
Inquire about the parameter corresponding to _XOPEN_XPG2.
_SC_XOPEN_XPG3
Inquire about the parameter corresponding to _XOPEN_XPG3.
_SC_XOPEN_XPG4
Inquire about the parameter corresponding to _XOPEN_XPG4.
_SC_CHAR_BIT
Inquire about the number of bits in a variable of type char.
_SC_CHAR_MAX
Inquire about the maximum value which can be stored in a variable of type char.
_SC_CHAR_MIN
Inquire about the minimum value which can be stored in a variable of type char.
_SC_INT_MAX
Inquire about the maximum value which can be stored in a variable of type int.
_SC_INT_MIN
Inquire about the minimum value which can be stored in a variable of type int.
_SC_LONG_BIT
Inquire about the number of bits in a variable of type long int.
_SC_WORD_BIT
Inquire about the number of bits in a variable of a register word.
_SC_MB_LEN_MAX
Inquire the maximum length of a multi-byte representation of a wide character value.
_SC_NZERO
Inquire about the value used to internally represent the zero priority level for the process execution.
SC_SSIZE_MAX
Inquire about the maximum value which can be stored in a variable of type ssize_t.
_SC_SCHAR_MAX
Inquire about the maximum value which can be stored in a variable of type signed char.
_SC_SCHAR_MIN
Inquire about the minimum value which can be stored in a variable of type signed char.
_SC_SHRT_MAX
Inquire about the maximum value which can be stored in a variable of type short int.
_SC_SHRT_MIN
Inquire about the minimum value which can be stored in a variable of type short int.
_SC_UCHAR_MAX
Inquire about the maximum value which can be stored in a variable of type unsigned char.
_SC_UINT_MAX
Inquire about the maximum value which can be stored in a variable of type unsigned int.
_SC_ULONG_MAX
Inquire about the maximum value which can be stored in a variable of type unsigned long int.
_SC_USHRT_MAX
Inquire about the maximum value which can be stored in a variable of type unsigned short int.
_SC_NL_ARGMAX
Inquire about the parameter corresponding to NL_ARGMAX.
_SC_NL_LANGMAX
Inquire about the parameter corresponding to NL_LANGMAX.
_SC_NL_MSGMAX
Inquire about the parameter corresponding to NL_MSGMAX.
_SC_NL_NMAX
Inquire about the parameter corresponding to NL_NMAX.
_SC_NL_SETMAX
Inquire about the parameter corresponding to NL_SETMAX.
_SC_NL_TEXTMAX
Inquire about the parameter corresponding to NL_TEXTMAX.