R CMD checkすると、ドキュメントの存在しない関数は警告がでるのだけど、パッケージ内部で使うための関数も引っかかってしまう。

1.1.3 Package subdirectories

if a package pkg contains user-level objects which are for “internal” use only, it should provide a file pkg-internal.Rd which documents all such objects, and clearly states that these are not meant to be called by the user.

gridのRdを読めと書いてあったので読んでみる(R-2.11.0/src/library/grid/man/grid-internal.Rd)。

\name{grid-internal}

\alias{grid.legend}
\alias{grid.multipanel}
\alias{grid.panel}
\alias{grid.strip}
\alias{is.unit}
\alias{layoutRegion}
\alias{viewport.layout}
\alias{viewport.transform}
\alias{layout.heights}
\alias{layout.widths}
\alias{layout.torture}

\title{Internal Grid Functions}
\description{
  Internal Grid functions
}
\details{
  These are not to be called by the user (or in some cases are just
  waiting for proper documentation to be written :).
}
\keyword{ internal }

こんな感じ