.subset2 ` are essentially equivalent to the `
[ [ ](/link/%5B?package=base&version=3.6.2) ` and ` [ [[
](/link/%5B%5B?package=base&version=3.6.2) ` operators, except that methods
dispatch does not take place. This is to avoid expensive unclassing when
applying the default method to an object. They should not normally be invoked
by end users. Note that unlike the operators they are builtins and not
specials (all arguments are evaluated) and hence do not allow missing
arguments.

` .getRequiredPackages2 ` attaches all the packages mentioned in the ` Depends
` field: failure to find a package is an error. It also checks the versions of
the packages found against the ` Depends ` field.

` .getRequiredPackages ` is a wrapper to ` .getRequiredPackages2 ` using a `
DESCRIPTION ` file.

The function ` .isMethodsDispatchOn() ` returns ` TRUE ` if the S4 method
dispatch has been turned on in the evaluator (usually by loading package
methods  ). It is meant for  R  internal use only.

` sys.save.image ` is a system function that is called by ` q() ` and its GUI
analogs; ` sys.load.image ` is called by the startup code. These functions
should not be called directly and are subject to change.

` sys.save.image ` closes all connections first, to ensure that it is able to
open a connection to save the image. This is appropriate when called from `
q() ` and allies, but reinforces the warning that it should not be called
directly.

` [ row.names ](/link/row.names?package=base&version=3.6.2) ` can be stored
internally in compact form. ` .set_row_names(n) ` generates that form for
automatic row names of length ` n ` , to be assigned to ` attr(<a data frame>,
"row.names") ` . ` .row_names_info ` gives information on the internal form of
the row names for a data frame: for details of what information see the
argument ` type ` .

` .GenericArgsEnv ` and ` .ArgsEnv ` are environments that contain closures
with the argument lists that the primitives would have had had they been
closures. All the primitives that are internal S3 generics have corresponding
members of ` .GenericArgsEnv ` and the remaining non-language-element
primitives correspond to ` .ArgsEnv ` . See the ‘R Internals’ manual for
further details. They are used by ` [ args
](/link/args?package=base&version=3.6.2) ` and ` [ print.default
](/link/print.default?package=base&version=3.6.2) ` and the QC functions ` [
codoc ](/link/codoc?package=base&version=3.6.2) ` and ` [ checkS3methods
](/link/checkS3methods?package=base&version=3.6.2) ` .

` findPackageEnv ` is invoked by the unserialize code to set a saved
environment if possible.

` .TAOCP1997init ` is the initialization code for the ` "Knuth-TAOCP" ` [ RNG
](/link/RNG?package=base&version=3.6.2) .

` .gt ` and ` .gtn ` are callbacks from ` [ rank
](/link/rank?package=base&version=3.6.2) ` and ` [ is.unsorted
](/link/is.unsorted?package=base&version=3.6.2) ` used for S3 classed objects.

` .primTrace ` and ` .primUntrace ` are the [ primitive
](/link/primitive?package=base&version=3.6.2) functions underlying ` [ trace
](/link/trace?package=base&version=3.6.2) ` and ` [ untrace
](/link/untrace?package=base&version=3.6.2) ` respectively.

` .Date ` , ` .POSIXct ` , ` .POSIXlt ` and ` .difftime ` are class
generators.

` .cache_class ` caches the inheritance of an S4 class for use in S3 method
dispatch. With ` NULL ` second argument it returns the cached inheritance, for
diagnostic use.

` .popath ` is a variable created at startup which records where the
translations  package in use is.

` .mapply ` and ` .detach ` are ‘bare-bones’ versions for use in other  R
packages.

` .maskedMsg ` is a utility called both from ` [ attach
](/link/attach?package=base&version=3.6.2) () ` and ` [ library
](/link/library?package=base&version=3.6.2) () ` for consistency to produce
the warning message.

Objects starting ` .C_ ` and ` .F_ ` are references to registered C and
Fortran entry points.

` .fixupGFortranStdout ` and ` .fixupGFortranStderr ` are h