getconf(1) — Commands
NAME
getconf − Displays system configuration variable values
SYNOPSIS
getconf [−v specification] system_var
getconf [−v specification] path_var pathname
STANDARDS
Interfaces documented on this reference page conform to industry standards as follows:
getconf: XPG4, XPG4-UNIX
Refer to the standards(5) reference page for more information about industry standards and associated tags.
OPTIONS
−v specification
Indicates a specification and version for which configuration variables are to be determined. If this option is not specified, the values returned will correspond to an implementation default XBS5-conforming compilation environment.
The specification can be one of the following symbolic constants:
XBS5_ILP32_OFF32
XBS5_ILP32_OFFBIG
XBS5_LP64_OFF64
XBS5_LPBIG_OFFBIG
These four constants have corresponding system standards configuration variables. The names are the same except for a leading underscore in the name of the configuration variable; for example, the specification constant XBS5_ILP32_OFF32 corresponds to the configuration variable _XBS5_ILP32_OFF32.
If a getconf command is issued with one of these configuration variables (for example, _XBS5_LPBIG_OFFBIG) and does not return -1 or “undefined”, then a following getconf command with a −v specification of XBS5_LPBIG_OFFBIG will determine values for configuration variables corresponding to the XBS5_LPBIG_OFFBIG compilation environment. For example:
%sh
$ outstr=‘getconf _XBS5_LPBIG_OFFBIG‘
$ if ["$outstr"!="-1"] && ["$outstr"!="undefined"]
> then
> cvars=‘getconf -v XBS5_LPBIG_OFFBIG XVS5_LPBIG_OFFBIG_id‘
> fi
The id in the system-wide configuration variable identifies which configuration variables are to be returned. See the description of XBS5_∗ variables under the heading “System Standards Configuration Variables” for details about the id suffix.
OPERANDS
specification
Name of a symbolic constant. (The symbolic constant names are listed in the DESCRIPTION section under the heading “Specification Constants”.)
system_var
Name of a system-wide configuration variable. (These variable names are listed in the DESCRIPTION section under the headings “System-Wide Configuration Variables” and “System Standards Configuration Variables”.)
path_var
Name of a system path-configuration variable. (These variable names are listed in the DESCRIPTION section under the heading “System Path Configuration Variables”.)
pathname
A path name for the path_var variable.
DESCRIPTION
In the system_var synopsis form, the getconf utility writes, to the standard output, the value of the variable specified in the system_var operand.
In the path_var synopsis form, the getconf utility writes, to the standard output, the value of the variable specified by the path_var operand for the path specified by the pathname operand.
In both cases, the value reflects conditions in the current operating environment.
The system_var argument specifies system-wide configuration variables whose values are valid throughout the system. There are two kinds of system-wide configuration values:
•System-wide configuration variables
•System standards configuration variables
The path_var argument specifies system path-configuration variables whose values contain information about paths and the path structure in the system.
Specification Variables
Specifications return the value -1 or “undefined” if the implementation of the standard in the system does not support the configuration defined by the specification and a value other than -1 if the implementation does support the configuration. If these are undefined, the sysconf() function can be used to determine whether the configuration is provided for a particular invocation of the application.
XBS5_ILP_OFF32
This symbolic constant specifies that the implementation is to provide a C-language compilation environment with 32-bit int, long, pointer, and off_t types.
XBS5_ILP323_OFFBIG
This symbolic constant specifies that the implementation is to provide a C-language compilation environment with 32-bit int, long, and pointer types and an off_t type using at least 64 bits.
XBS5_LP64_OFF64
This symbolic constant specifies that the implementation is to provide a C-language compilation environment with a 32-bit int type and 64-bit long, pointer, and off_t types.
XBS5_LPBIG_OFFBIG
This symbolic constant specifies that the implementation is to provide a C-language compilation environment with an int type using at least 32 bits and long, pointer, and off_t types using at least 64 bits.
System-Wide Configuration Variables
System-wide configuration variables contain the minimum values met throughout all portions of the system. The following list defines the system-wide configuration variables used with the getconf command:
ARG_MAX
The maximum length, in bytes, of the arguments for one of the exec functions, including environment data.
ATEXIT_MAX
[XPG4-UNIX] The maximum number of functions that can be registered with atexit() per process.
BC_BASE_MAX
The maximum value allowed for the obase variable with the bc command.
BC_DIM_MAX
The maximum number of elements permitted in an array by the bc command.
BC_SCALE_MAX
The maximum value allowed for the scale variable with the bc command.
BC_STRING_MAX
The maximum length of string constants accepted by the bc command.
CHARCLASS_NAME_MAX
The maximum number of bytes in a character class name.
CHAR_BIT
Number of bits in a type of char.
CHAR_MAX
The maximum value of a type char.
CHAR_MIN
The minimum value of a type char.
CHILD_MAX
The maximum number of simultaneous processes for each real user ID.
CLK_TCK
The number of clock ticks per second. The value of CLK_TCK may be variable, and it should not be assumed that CLK_TCK is a compile-time constant.
COLL_WEIGHTS_MAX
The maximum number of weights that can be assigned to an entry in the LC_COLLATE locale-dependent information in a locale-definition file.
CS_PATH
A value for the PATH environment variable that finds all standard utilities.
DATAKEYS_MAX
[Tru64 UNIX] The maximum number of data keys that may be created per process.
EXPR_NEST_MAX
The maximum number of expressions that can be nested within parentheses by the expr command.
INT_MAX
The maximum value of an int.
INT_MIN
The minimum value of an int.
LINE_MAX
The maximum length, in bytes, of a command’s input line (either standard input or another file) when the utility is described as processing text files. The length includes room for the trailing newline character.
LONG_BIT
Number of bits in a long int.
LONG_MAX
The maximum value of a long int.
LONG_MIN
The minimum value of a long int.
MB_LEN_MAX
The maximum number of bytes in a character for any supported locale.
NGROUPS_MAX
The maximum number of simultaneous supplementary group IDs for each process.
NL_ARGMAX
The maximum value of digit in calls to the printf() and scanf() functions.
NL_LANGMAX
The maximum number of bytes in a LANG name.
NL_MSGMAX
The maximum message number.
NL_NMAX
[Tru64 UNIX] The maximum number of bytes in an N-to-1 collation mapping.
NL_SETMAX
The maximum set number.
NL_TEXTMAX
The maximum number of bytes in a message string.
NZERO
Default process priority.
OPEN_MAX
The maximum number of files that one process can have open at one time.
PAGE_SIZE
[XPG4-UNIX] The page size granularity for memory regions.
PASS_MAX
[Tru64 UNIX] The maximum number of characters returned by getpass() (not including terminating null).
PATH
A value for the PATH environment variable that finds all standard utilities.
PRODUCT_NAME
[Tru64 UNIX] The official name of the installed operating system product.
RE_DUP_MAX
The maximum number of repeated occurrences of a regular expression permitted when using the interval-notation parameters, such as the m and n parameters with the ed command.
SCHAR_MAX
The maximum value of a type signed char.
SCHAR_MIN
The minimum value of a type signed char.
SHRT_MAX
The maximum value of a type short.
SHRT_MIN
The minimum value of a type short.
SSIZE_MAX
The maximum value that can be stored in an object of type ssize_t.
STREAM_MAX
The number of streams that one process can have open at one time.
SYSTEM_BANNER
[Tru64 UNIX] The official system banner. The banner typically consists of the vendor name followed by the product name.
SYSTEM_VERSION
[Tru64 UNIX] The product version information.
TMP_MAX
The minimum number of unique path names generated by tmpnam(). Maximum number of times an application can call tmpnam() reliably.
TZNAME_MAX
The maximum number of bytes supported for the name of a time zone (not the length of the TZ environmental variable).
UCHAR_MAX
The maximum value of a type unsigned char.
UINT_MAX
The maximum value of a type unsigned int.
ULONG_MAX
The maximum value of a type unsigned long int.
USHRT_MAX
The maximum value of a type unsigned short int.
VENDOR_ABBREV
[Tru64 UNIX] The official abbreviated company name of the operating system manufacturer. If no value was specified for this variable, the VENDOR_NAME value is returned.
VENDOR_NAME
[Tru64 UNIX] The official company name of the operating system manufacturer.
WORD_BIT
Number of bits in a word or type int.
System Standards Configuration Variables
System standards configuration variables contain the minimum values required by a particular system standard. The prefixes of the variables indicate that the variables contain the minimum values for system characteristics required by particular standards. The correspondence between the prefixes and standards is as follows:
| Prefix | Standard |
| _POSIX_ | POSIX 1003.1 (POSIX.1) |
| POSIX2_ | POSIX 1003.2 (POSIX.2) |
| _XOPEN_ | X/Open |
| XBS5_ or _XBS5_ | X/Open Version 5.1 |
| _AES_ | Open Software Foundation’s AES system standard |
System standards are system-wide minimums that the system meets to support the particular system standard. Actual configuration values may exceed these standards. The system standards configuration variables for the getconf command are defined as follows:
_AES_OS_VERSION
[Tru64 UNIX] The integer value indicating the revision of the Application Environment Specification to which the implementation is compliant.
_POSIX_ARG_MAX
The length of the arguments for one of the exec functions, in bytes, including environment data.
_POSIX_CHILD_MAX
The maximum number of simultaneous processes for each real user ID.
_POSIX_JOB_CONTROL
This variable has a value of 1 if the system supports job control; otherwise, the variable is undefined.
_POSIX_LOCALEDEF
This variable has a value other than −1 if the implementation supports the creation of locales by the localedef utility.
_POSIX_LINK_MAX
The maximum value of a file’s link count.
_POSIX_MAX_CANON
The maximum number of bytes in a terminal canonical input queue.
_POSIX_MAX_INPUT
The maximum number of bytes for which space will be available in a terminal input queue.
_POSIX_NAME_MAX
The maximum number of bytes in a file name.
_POSIX_NGROUPS_MAX
The maximum number of simultaneous supplementary group IDs for each process.
_POSIX_OPEN_MAX
The maximum number of files that one process can have open at one time.
_POSIX_PATH_MAX
The maximum number of bytes in a path name.
_POSIX_PIPE_BUF
The maximum number of bytes that can be written atomically when writing to a pipe.
_POSIX_REENTRANT_FUNCTIONS
[Tru64 UNIX] This variable has a value of 1 if the system supports POSIX reentrant functions; otherwise, the variable is undefined.
_POSIX_SAVED_IDS
This variable has a value of 1 if each process has a saved set-user-ID and a saved set-group-ID; otherwise, the variable is undefined.
_POSIX_SSIZE_MAX
The maximum value that can be stored in an object of type ssize_t.
_POSIX_STREAM_MAX
The number of streams that one process can have open at one time.
_POSIX_THREAD_ATTR_STACKSIZE
[Tru64 UNIX] This variable has a value of 1 if the system supports the POSIX threads stack size attribute; otherwise, the variable is undefined.
_POSIX_THREAD_PRIO_INHERIT
This variable has a value other than −1 if the implementation supports the priority inheritance option.
_POSIX_THREAD_PRIORITY_SCHEDULING
This variable has a value other than −1 if the implementation supports the thread execution scheduling option.
_POSIX_THREADS
[Tru64 UNIX] This variable has a value of 1 if the system supports POSIX threads; otherwise, the variable is undefined.
_POSIX_TZNAME_MAX
The maximum number of bytes supported for the name of a time zone (not the length of the TZ environmental variable).
_POSIX_VERSION
The date of approval of the most current version of the POSIX.1 standard that the system supports. The date is a 6-digit number, with the first 4 digits signifying the year and the last 2 digits the month. Different versions of the POSIX.1 standard are periodically approved by the IEEE Standards Board, and the date of approval is used to distinguish between different versions.
POSIX2_BC_BASE_MAX
The maximum value allowed for the obase variable with the bc command.
POSIX2_BC_DIM_MAX
The maximum number of elements permitted in an array by the bc command.
POSIX2_BC_SCALE_MAX
The maximum value allowed for the scale variable with the bc command.
POSIX2_BC_STRING_MAX
The maximum of length string constants accepted by the bc command.
POSIX2_CHAR_TERM
One or more terminal types capable of all operations described in ISO/IEC 9945. This value need not be present on a system not supporting the User Portability Utilities Option.
POSIX2_COLL_WEIGHTS_MAX
The maximum number of weights that can be assigned to an entry of the LC_COLLATE locale variable in a locale-definition file.
POSIX2_EXPR_NEST_MAX
The maximum number of expressions that can be nested within parentheses by the expr command.
POSIX2_LINE_MAX
The maximum length, in bytes, of a command’s input line (either standard input or another file) when the utility is described as processing text files. The length includes room for the trailing newline character.
POSIX2_LOCALEDEF
This variable has a value of 1 if the system supports the creation of new locales with the localedef command; otherwise, the variable is undefined.
POSIX2_RE_DUP_MAX
The maximum number of repeated occurrences of a regular expression permitted when using the interval-notation parameters, such as the m and n parameters with the ed command.
POSIX2_UPE
This variable has a value of 1 if the system supports the User Portability Utilities Option; otherwise, the variable has a value of 0 (zero).
POSIX2_VERSION
The date of approval of the most current version of the POSIX.2 standard that the system supports. The date is a 6-digit number, with the first 4 digits signifying the year and the last 2 digits the month. Different versions of the POSIX.2 standard are periodically approved by the IEEE Standards Board, and the date of approval is used to distinguish between different versions.
POSIX2_C_BIND
This variable has a value of 1 if the system supports the optional C Language Development Facilities specified by POSIX.2 and the optional C Language Bindings Option from POSIX.2; otherwise, the variable is undefined.
POSIX2_C_DEV
This variable has a value of 1 if the system supports the optional C Language Development Utilities from POSIX.2; otherwise, the variable is undefined.
POSIX2_C_VERSION
This value indicates the version of the interfaces described in the C-Language Bindings Option section of the XPG4 standard. This value changes with each published version of ISO/IEC 9945 to indicate the 4-digit year and 2-digit month that the standard was approved by the IEEE Standards Board.
POSIX2_FORT_DEV
This variable has a value of 1 if the system supports the FORTRAN Development Utilities Option from POSIX.2; otherwise, the variable is undefined.
POSIX2_FORT_RUN
This variable has a value of 1 if the system supports the FORTRAN Run-time Utilities Option from POSIX.2; otherwise, the variable is undefined.
POSIX2_SW_DEV
This variable has a value of 1 if the system supports the Software Development Utilities Option from POSIX.2; otherwise, the variable is undefined.
_XBS5_ILP32_OFF32
_XBS5_ILP32_OFFBIG
_XBS5_LP64_OFF64
_XBS5_LPBIG_OFFBIG
Same meanings as the −v specification variables. Note that the corresponding specification variables do not have a leading underscore. See “Specification Variables” for definitions.
_XBS5_ILP32_OFF32_id
_XBS5_ILP32_OFFBIG_id
_XBS5_ILP64_OFF64_id
_XBS5_LPBIG_OFFBIG_id
These variables specify values to be passed to utilities used in building an application. The name of the parameter establishes type-size constraints for the environment in which an application is being built: .
_XBS5_ILP32_OFF32_id
The int, long, pointer, and off_t types are treated as 32-bit types.
_XBS5_ILP32_OFFBIG_id
The int, long, and pointer types are treated as 32-bit types, and the off_t type is treated as a type with at least 64 bits.
_XBS5_LP64_OFF64_id
The int type is treated as a 32-bit type, and the long, pointer, and off_t types are treated as 64-bit types
_XBS5_LPBIG_OFFBIG_id
The int type is treated as a type with at least 32 bits, and the long, pointer, and off_t types are treated as types with at least 64 bits.
The parameter suffix (id) identifies the component affected by the type-size constraint:
CFLAGS
The value of the parameter is the set of initial options (compilation options) to be given to cc or c89.
LDFLAGS
The value of the parameter is the set of final options (loader options) to be given to cc or c89.
LIBSThe value of the parameter is the set of libraries to be given to cc or c89.
LINTThe value of the parameter is the set of checking options to be given to lint.
In all cases, if sysconf (_SC_XBS5_ILP32_OFFBIG) returns -1, the meaning of the passed values is unspecified.
_XOPEN_CRYPT
This variable has a value other than -1 if the implementation supports the X/Open Encryption Feature Group.
_XOPEN_ENH_I18N
This variable has a value other than -1 if the implementation supports the X/Open Enhanced Internationalization Feature Group.
_XOPEN_LEGACY
This variable has a value other than −1 if the implementation supports the Legacy Feature Group.
_XOPEN_REALTIME
This variable has a value other than −1 if the implementation supports the X/Open Realtime Feature Group.
_XOPEN_REALTIME_THREADS
This variable has a value other than −1 if the implementation supports the X/Open Realtime Threads Feature Group.
_XOPEN_SHM
This variable has a value other than -1 if the implementation supports the X/Open Shared Memory Feature Group.
_XOPEN_VERSION
An integer indicating the most current version of the X/OPEN standard that the system supports.
_XOPEN_XCU_VERSION
An integer value indicating the version of the XCU specification to which the implementation conforms. If the value is -1, no commands and utilities are provided on the implementation.
_XOPEN_XPG2
This variable is defined only if the implementation supports the X/Open Portability Guide, Volume 2, January 1987, XVS System Calls and Libraries.
_XOPEN_XPG3
This variable is defined only if the implementation supports the X/Open Specification, February 1992, System Interfaces and Headers, Issue 3.
_XOPEN_XPG4
This variable is defined only if the implementation supports the X/Open CAE Specification, July 1992, Systems Interfaces and Headers, Issue 4.
System Path Configuration Variables
LINK_MAX
The maximum value of a file’s link count. If the pathname argument refers to a directory, the value returned applies to the directory itself.
MAX_CANON
The maximum number of bytes in a terminal canonical input queue. If the pathname argument does not specify a terminal file, the getconf command exits with a nonzero value.
MAX_INPUT
The maximum number of bytes for which space will be available in a terminal input queue. If the pathname argument does not specify a terminal file, the getconf command exits with a nonzero value.
NAME_MAX
The maximum number of bytes in a file name. If the pathname argument specifies a directory, the value returned applies to the file names within the directory.
PATH_MAX
The maximum number of bytes in a path name. If the pathname argument specifies a directory, the value returned is the maximum length of a relative path name when the specified directory is the working directory.
PIPE_BUF
The maximum number of bytes that can be written atomically when writing to a pipe. If the pathname argument specifies a FIFO or a pipe, the value returned applies to that object. If the pathname argument specifies a directory, the value returned applies to any FIFO created in that directory. If the pathname argument does not specify a directory or a FIFO file, the getconf command exits with a nonzero value.
_POSIX_CHOWN_RESTRICTED
This variable has a value of 1 when the use of the chown function is restricted to a process with appropriate privileges and the group ID of a file can only be changed to the effective group ID of the process or to one of its supplementary group IDs. If the variable is undefined, it varies in the system, depending upon the path.
_POSIX_NO_TRUNC
This variable has a value of 1 when path names longer than the limit specified by the NAME_MAX variable will generate an error. If the variable is undefined, it varies in the system, depending upon the path.
_POSIX_VDISABLE
When this variable has a value of 1, terminal special characters, which are defined in the <termios.h> header file, can be disabled. If the pathname argument does not specify a terminal file, the getconf command will exit with a nonzero value.
EXIT STATUS
The following exit values are returned:
0The specified variable is valid and information about its current state has been displayed successfully.
>0An error occurred.
EXAMPLES
1.To display the value of the ARG_MAX environment variable, enter:
getconf ARG_MAX
2.To display the value of the PATH_MAX environmental variable for the /usr directory, enter:
getconf PATH_MAX /usr
This sequence returns the following message:
The value of PATH_MAX in /usr is 1023
ENVIRONMENT VARIABLES
The following environment variables affect the execution of getconf:
LANG
Provides a default value for the internationalization variables that are unset or null. If LANG is unset or null, the corresponding value from the default locale is used. If any of the internationalization variables contain an invalid setting, the utility behaves as if none of the variables had been defined.
LC_ALL
If set to a non-empty string value, overrides the values of all the other internationalization variables.
LC_CTYPE
Determines the locale for the interpretation of sequences of bytes of text data as characters (for example, single-byte as opposed to multibyte characters in arguments).
LC_MESSAGES
Determines the locale for the format and contents of diagnostic messages written to standard error.
NLSPATH
Determines the location of message catalogues for the processing of LC_MESSAGES.
FILES
/usr/include/limits.h
Defines system configuration variables.
/usr/include/unistd.h
Defines system configuration variables.
/usr/include/termio.h
Defines terminal characteristics.
SEE ALSO
Commands: env(1)
Functions: pathconf(2)