% File src/library/base/man/ns-lowlev.Rd
% Part of the R package, http://www.R-project.org
% Copyright 1995-2007 R Core Development Team
% Distributed under GPL 2 or later

\name{ns-lowlev}
\title{Low Level Name Space Support Functions}

\alias{loadingNamespaceInfo}
\alias{saveNamespaceImage}

\description{
  Low level name space support functions.
}
\usage{
loadingNamespaceInfo()
saveNamespaceImage(package, rdafile, lib.loc = NULL,
                   keep.source = getOption("keep.source.pkgs"),
                   compress = TRUE)
}
\arguments{
  \item{package}{string naming the package/name space to load.}
  \item{rdafile}{name of file to save to.}
  \item{lib.loc}{character vector specifying library search path.}
  \item{keep.source}{logical specifying whether to retain source.}
  \item{compress}{option passed to \code{\link{save}}.}
}
\details{
  The functions \code{loadNamespace} and \code{attachNamespace} are
  usually called implicitly when \code{library} is used to load a name
  space and any imports needed.  However it may be useful to call
  these functions directly at times.

  \code{loadNamespace} loads the specified name space and registers it in
  an internal data base.  A request to load a name space that is already
  loaded has no effect.  The arguments have the same meaning as the
  corresponding arguments to \code{library}.  After loading,
  \code{loadNamespace} looks for a hook function named
  \code{\link{.onLoad}} as an internal variable in the name space (it
  should not be exported). This function is called with the same arguments
  as \code{.First.lib}.  Partial loading is used to support installation with
  the \option{--save} option.

  \code{loadNamespace} does not attach the name space it loads to the
  search path.  \code{attachNamespace} can be used to attach a frame
  containing the exported values of a name space to the search path.
  The hook function \code{\link{.onAttach}} is run after the name space
  exports are attached.

  \code{loadedNamespaces} returns a character vector of the names of
  the loaded name spaces.

  \code{unloadNamespace} can be used to force
  a name space to be unloaded.  An error is signaled if the name space
  is imported by other loaded name spaces.  If defined, a hook
  function \code{\link{.onUnload}} is run
  before removing the name space from the internal registry.
  \code{unloadNamespace} will first \code{\link{detach}} a package of
  the same name if one is on the path, thereby running a
  \code{.Last.lib} function in the package if one is exported.

  \code{loadingNamespaceInfo} returns a list of the arguments that
  would be passed to \code{.onLoad} when a name space is being loaded.
  An error is signaled of a name space is not currently being loaded.

  \code{saveNamespaceImage} is used to save name space images for
  packages installed with \option{--save}.
}
\keyword{internal}
\author{Luke Tierney}