getconf(C)

getconf -- print configuration dependent values

Syntax

getconf system_variable

getconf path_variable pathname

Description

The getconf command writes the value of configuration dependent variables to standard output.

In the first syntax, getconf writes the value of the variable specified by system_variable.

In the second syntax, getconf writes the value of the variable specified by path_variable for the specified pathname.

If system_variable or path_variable is a legal variable, but is not defined on the current system or in pathname, getconf will display:

undefined

The following variables are recognized as system variables:

ARG_MAX: Maximum length of an argument. The minimum length is defined by {POSIX_ARG_MAX} (see below).
BC_BASE_MAX: Maximum obase values as permitted by the bc command. The minimum value is defined by {POSIX2_BC_BASE_MAX} (see below).
BC_DIM_MAX: Maximum number of array elements permitted by bc. The minimum number is defined by {POSIX2_BC_DIM_MAX} (see below).
BC_SCALE_MAX: Maximum value of scale allowed by bc. The minimum value is defined by {POSIX2_BC_SCALE_MAX} (see below).
BC_STRING_MAX: Maximum length of a string constant accepted by bc. The minimum length is defined by {POSIX2_BC_STRING_MAX} (see below).
CHARCLASS_NAME_MAX: Maximum number of bytes in a character class name.
CHAR_BIT: The number of bits in a type char variable.
CHAR_MAX: The highest possible value of a type char variable.
CHAR_MIN: The minimum possible value of a type char variable.
CHILD_MAX: Maximum number of simultaneous processes per real user ID. The minimum number is defined by {POSIX_CHILD_MAX} (see below).
CLK_TCK: Number of clock ticks per second.
COLL_WEIGHTS_MAX: Maximum number of weights that can be assigned to LC_COLLATE variable. The minimum number is defined by {POSIX2_COLL_WEIGHTS_MAX} (see below).
CS_PATH: The value of the PATH environment variable.
EXPR_NEST_MAX: The maximum number of expressions that can be nested within parentheses by the expr(C) command. The minimum number is defined by {POSIX2_EXPR_NEST_MAX} (see below).
INT_MAX: Maximum value of a type int variable.
INT_MIN: Minimum value of a type int variable.
IOV_MAX: Maximum number of iovec structures that can be used by readv(S) and writev(S) system calls.
KERNEL_CLISTS: Number of clists allocated.
KERNEL_CLISTS_MAX: Maximum number of clists.
KERNEL_DISK: Number of disk drives supported.
KERNEL_DISK_MAX: Maximum number of disk drives that can be supported.
KERNEL_FILE: Size of file table.
KERNEL_FILE_MAX: Maximum size of file table.
KERNEL_FLCKREC: Number of record locks.
KERNEL_FLCKREC_MAX: Maximum number of record locks.
KERNEL_INODE: Size of inode table.
KERNEL_INODE_MAX: Maximum size of inode table.
KERNEL_MOUNT: Size of mount table.
KERNEL_MOUNT_MAX: Maximum size of mount table.
KERNEL_PINODE: Size of High Performance Pipe System (HPPS) inode table.
KERNEL_PINODE_MAX: Maximum size of High Performance Pipe System (HPPS) inode table.
KERNEL_PROC: Size of process table.
KERNEL_PROC_MAX: Maximum size of process table.
KERNEL_REGION: Size of region table.
KERNEL_REGION_MAX: Maximum size of region table.
KERNEL_S5INODE: Size of s5inode table.
KERNEL_S5INODE_MAX: Maximum size of s5inode table.
LINE_MAX: The default maximum length, in bytes, of a command's input line. The length includes the trailing newline.
LONG_BIT: Set to the number of bits in a variable of type long int.
LONG_MAX: Set to the maximum number of bits in a variable of type long int.
LONG_MIN: Set to the minimum number of bits in a variable of type long int.
MB_LEN_MAX: Maximum number of bytes in a character, for any supported locale.
NGROUPS_MAX: This is the maximum number of simultaneous supplementary group IDs available to a process. The minimum number is defined by {POSIX_NGROUPS_MAX} (see below).
NL_ARGMAX: This is the maximum value of the variable digit as passed to the printf(S) and scanf(S) functions.
NL_LANGMAX: This is the maximum number of permissible bytes in a LANG name.
NL_MSGMAX: Set to the maximum number of a message.
NL_NMAX: This is set to the maximum number of permissible bytes in an N-to-1 collation mapping.
NL_SETMAX: The maximum set number.
NL_TEXTMAX: This is set to the maximum number of allowable bytes in a message string.
NZERO: This is the default process priority.
OPEN_MAX: The maximum number of per-process open files. The minimum number is defined by {POSIX_OPEN_MAX} (see below).
PASS_MAX: The maximum number of significant bytes in a
PATH: The path through which the shell searches for a specified command.
_POSIX_ARG_MAX: Maximum length of an argument, including environment data, to the exec(S) function, and the minimum value to which {ARG_MAX} can be set.
_POSIX_CHILD_MAX: Maximum number of simultaneous processes per real user ID, and the minimum value to which {CHILD_MAX} can be set.
_POSIX_JOB_CONTROL: If set to a value other than -1, the implementation supports job control.
_POSIX_LINK_MAX: Maximum number of permitted links to a single file, and the minimum value to which {LINK_MAX} can be set.
_POSIX_MAX_CANON: Maximum number of permitted bytes in a terminal canonical input queue, and the minimum value to which {MAX_CANON} can be set.
_POSIX_MAX_INPUT: Maximum number of permitted bytes in a terminal input queue. The minimum value to which {MAX_INPUT} can be set.
_POSIX_NAME_MAX: Maximum length (in bytes) of a filename, excluding terminating null, and the minimum value to which {NAME_MAX} can be set.
_POSIX_NGROUPS_MAX: Maximum number of simultaneous supplementary group IDs per process, and the minimum value to which {NGROUPS_MAX} can be set.
_POSIX_OPEN_MAX: Maximum number of per-process open files that can be simultaneously open, and the minimum value to which {OPEN_MAX} can be set.
_POSIX_PATH_MAX: Maximum length (in bytes) of a pathname, and the minimum value to which {PATH_MAX} can be set.
_POSIX_PIPE_BUF: Maximum number of bytes guaranteed to be atomic when writing to a pipe, and the minimum value to which {PIPE_BUF} can be set.
_POSIX_SAVED_IDS: If this constant is defined with a value other than -1, each process has a saved user-ID and a saved set-group ID.
_POSIX_SSIZE_MAX: Set to the value that can be stored in an object of size size_t, and the minimum value to which {SSIZE_MAX} can be set.
_POSIX_STREAM_MAX: The maximum number of streams that a single process can have open at any one time, and the minimum value to which {STREAM_MAX} can be set.
_POSIX_TZNAME_MAX: The maximum number of bytes that can make up the name of a timezone, and the minimum value to which {TZNAME_MAX} can be set.
_POSIX_VERSION: Integer value indicating the version of the IEEE POSIX standard supported.
POSIX2_BC_BASE_MAX: Maximum obase values as permitted by the bc command, and the minimum value to which {BC_BASE_MAX} can be set.
POSIX2_BC_DIM_MAX: Maximum number of array elements permitted by bc, and the minimum value to which {BC_DIM_MAX} can be set.
POSIX2_BC_SCALE_MAX: Maximum value of scale allowed by bc, and the minimum value to which {BC_SCALE_MAX} can be set.
POSIX2_BC_STRING_MAX: Maximum length of a string constant accepted by bc, and the minimum value to which {BC_STRING_MAX} can be set.
POSIX2_C_BIND: A figure other than -1 indicates support for the C language.
POSIX2_C_DEV: A figure other than -1 indicates support for the C language development utilities.
POSIX2_C_VERSION: Value indicating the version of the IEEE POSIX.2 standard supported by the implementation. It also indicates whether the X/Open POSIX2 C-language binding feature group is supported.
POSIX2_CHAR_TERM: Indicates whether the system supports at least one terminal type. Set to -1 if it does not, otherwise set to a value other than -1.
POSIX2_COLL_WEIGHTS_MAX: Maximum number of weights that can be assigned to the LC_COLLATE variable, and the minimum value to which {COLL_WEIGHTS_MAX} can be set.
POSIX2_EXPR_NEST_MAX: The maximum number of expressions that can be nested within parentheses by the expr(C) command, and the minimum value to which {EXPR_NESTS_MAX} can be set.
POSIX2_FORT_DEV: If set to a value other than -1, the implementation supports the FORTRAN development utilities option.
POSIX2_FORT_RUN: If set to a value other than -1, the implementation supports the FORTRAN run-time utilities option.
POSIX2_LINE_MAX: The default maximum length, in bytes, of a command's input line. The length includes the trailing newline.
POSIX2_LOCALEDEF: If set to a value other than -1, the implementation supports the localedef(C) utility.
POSIX2_RE_DUP_MAX: This is the maximum number of permitted repetitions of a regular expression when using the interval notation \f{m,n\f}.
POSIX2_SW_DEV: If set to a value other than -1, the implementation supports the software development utilities option.
POSIX2_UPE: If set to a value other than -1, the implementation supports the user portability utilities extension (UPE) option.
POSIX2_VERSION: Value indicating the version of the IEEE POSIX.2 standard supported by the implementation.
RE_DUP_MAX: This is the maximum number of permitted repetitions of a regular expression when using the interval notation \f{m,n\f}.
SCHAR_MAX: Maximum value of a variable of type signed char.
SCHAR_MIN: Minimum value of a variable of type signed char.
SHRT_MAX: Maximum value of a variable of type short.
SHRT_MIN: Minimum value of a variable of type short.
SSIZE_MAX: Maximum value of an object of type ssize_t. The minimum length is defined by {POSIX_SSIZE_MAX} (see above).
STREAM_MAX: The number of streams that any one process can have open at one time. If defined, this value is the same as {FOPEN_MAX} as defined in <stdio.h>. The minimum length is defined by {POSIX_STREAM_MAX} (see above).
TMP_MAX: The minimum number of unique pathnames that can be generated by tmpnam(S). Also the maximum number of times that an application can reliably call tmpnam.
TZNAME_MAX: The name of a time-zone can consist of this maximum number of bytes (this is not the TZ variable. The minimum length is defined by {POSIX_TZNAME_MAX} (see above).
UCHAR_MAX: Maximum value of a variable of type unsigned char.
UINT_MAX: Maximum value of a variable of type unsigned int.
ULONG_MAX: Maximum value of a variable of type unsigned long int.
USHRT_MAX: Maximum value of a variable of type unsigned short int.
WORD_BIT: The number of bits in a word or a variable of type int.
_XOPEN_VERSION: This value indicates the version of the X/Open specification to which this implementation conforms.
_XOPEN_XCU_VERSION: This integer value indicates the version of the X/Open commands and utilities specification (XCU) to which this implementation conforms. If the value is -1, no commands or utilities are provided on the implementation. If the value is greater than or equal to 4, the functionality defined by the following symbols is supported:

{POSIX2_C_BIND}
{POSIX2_C_VERSION}
{POSIX2_CHAR_TERM}
{POSIX2_LOCALEDEF}
{POSIX2_UPE}
{POSIX2_VERSION}
_XOPEN_CRYPT: If defined, the implementation supports the X/Open Encryption Feature Group.
_XOPEN_ENH_I18N: If defined, the implementation supports the X/Open Enhanced Internationalization (I18N) Feature Group.
_XOPEN_SHM: If defined, the implementation supports the X/Open Shared Memory Feature Group.
_XOPEN_XPG2: If defined, this implementation supports the X/Open Portability Guide, Version 2; Volume 2, XVS System Calls and Libraries, January 1987, ISBN 0-444-70174-5.
_XOPEN_XPG3: If defined, this implementation supports the X/Open Portability Guide, Version 3; Volume 2, XSI System Interfaces and Headers, December 1988, ISBN 0-13-685843-0.
_XOPEN_XPG4: If defined, this implementation supports X/Open CAE Specification, System Interfaces and Headers, Issue 4, 1992, July 1992, ISBN 1-872630-47-2.

The following variables are recognized as path variables (they depend on a pathname):

LINK_MAX: This is the maximum number of permissible links to a single file. The minimum length is defined by {POSIX_LINK_MAX}.
MAX_CANON: Maximum number of permitted bytes in a terminal canonical input queue. The minimum length is defined by {POSIX_MAX_CANON}.
MAX_INPUT: Maximum number of permitted bytes in a terminal input queue. The minimum length is defined by {POSIX_MAX_INPUT}.
NAME_MAX: Maximum length (in bytes) of a filename, excluding terminating null. The minimum length is defined by {POSIX_NAME_MAX}.
PATH_MAX: Maximum length (in bytes) of a pathname. The minimum length is defined by {POSIX_PATH_MAX}.
PIPE_BUF: Maximum number of bytes guaranteed to be atomic when writing to a pipe. The minimum length is defined by {POSIX_PIPE_BUF}.
_POSIX_CHOWN_RESTRICTED: If this is defined with a value other than -1, the chown(S) routine can only be executed by a process with appropriate privileges. In addition, the use of chown is restricted to the ability to change the group ID of a file to the effective group ID of the process or to one of its supplementary group ID.
_POSIX_NO_TRUNC: If this is set to a value other than -1, a pathname component longer than {NAME_MAX} will generate an error.
_POSIX_VDISABLE: If this value is set to -1, terminal special characters defined in <termio.h> will be disabled.

Exit values

getconf returns 0 (zero) if the specified variable exists or is undefined; a positive non-zero value is returned if the variable is invalid or an error occurs.

Examples

Entering the command getconf KERNEL_PROC will return the current size of the dynamic process table.

Limitations

The inclusion of a variable in one of the above tables does not imply that its value can be altered by reconfiguring the system; some of the values are fixed.

Standards conformance

getconf is conformant with:

ISO/IEC DIS 99452:1992, Information technology Portable Operating System Interface (POSIX) Part 2: Shell and Utilities (IEEE Std 1003.21992);
X/Open CAE Specification, Commands and Utilities, Issue 4, 1992.