NAME
getconf —
retrieve standard configuration
variables
SYNOPSIS
getconf |
[-v environment]
path_var file |
getconf |
[-v environment]
system_var |
DESCRIPTION
Thegetconf utility prints the value of a POSIX or
X/Open path or system configuration variable to the standard output. If the
specified variable is undefined, the string
“undefined” is output.
The first form of the command, with two mandatory arguments,
retrieves file- and file system-specific configuration variables using
pathconf(2). The second form, with a single argument,
retrieves system configuration variables using
confstr(3) and
sysconf(3), depending on the type of variable. As an extension, the
second form can also be used to query static limits from
<limits.h>.
All
sysconf(3) and
pathconf(2) variables use the same name as the manifest
constants defined in the relevant standard C-language bindings, including
any leading underscore or prefix. That is to say,
system_var might be ARG_MAX or
_POSIX_VERSION, as opposed to the
sysconf(3) names _SC_ARG_MAX or
_SC_VERSION. Variables retrieved from
confstr(3) have the leading
‘_CS_’ stripped off; thus,
_CS_PATH is queried by a
system_var of
“PATH”.
Programming Environments
The -v environment
option specifies a IEEE Std 1003.1-2001
(“POSIX.1”) programming environment under which the
values are to be queried. This option currently does nothing, but may in the
future be used to select between 32-bit and 64-bit execution environments on
platforms which support both. Specifying an environment which is not
supported on the current execution platform gives undefined results.
The standard programming environments are as follows:
POSIX_V7_ILP32_OFF32- Exactly 32-bit integer, long, pointer, and file offset. Supported platforms: None.
POSIX_V7_ILP32_OFFBIG- Exactly 32-bit integer, long, and pointer; at least 64-bit file offset. Supported platforms: None.
POSIX_V7_LP64_OFF64- Exactly 32-bit integer; exactly 64-bit long, pointer, and file offset. Supported platforms: x86_64.
POSIX_V7_LPBIG_OFFBIG- At least 32-bit integer; at least 64-bit long, pointer, and file offset. Supported platforms: None.
The command:
getconf
POSIX_V7_WIDTH_RESTRICTED_ENVSreturns a newline-separated list of environments in which the width of certain fundamental types is no greater than the width of the native C type long. At present, all programming environments supported by DragonFly have this property. Several of the confstr(3) variables provide information on the necessary compiler and linker flags to use the standard programming environments described above.
EXIT STATUS
The getconf utility exits 0 on
success, and >0 if an error occurs.
EXAMPLES
The command:
getconf PATHwill display the system default setting for the
PATH environment variable.
The command:
getconf NAME_MAX /tmpwill display the maximum length of a filename in the /tmp directory.
The command:
getconf -v _POSIX_V7_LPBIG_OFFBIG
LONG_MAXwill display the maximum value of the C type
long in the
POSIX_V7_LPBIG_OFFBIG programming environment, if
the system supports that environment.
DIAGNOSTICS
Use of a system_var or
path_var which is completely unrecognized is
considered an error, causing a diagnostic message to be written to standard
error. One which is known but merely undefined does not result in an error
indication. The getconf utility recognizes all of
the variables defined for IEEE Std 1003.1-2001
(“POSIX.1”), including those which are not currently
implemented.
SEE ALSO
STANDARDS
The getconf utility is expected to be
compliant with IEEE Std 1003.1-2001
(“POSIX.1”).
HISTORY
The getconf utility first appeared in
FreeBSD 5.0.
AUTHORS
Garrett A. Wollman <wollman@lcs.mit.edu>