

   FFoorreeiiggnn FFuunnccttiioonn IInntteerrffaaccee

        dyn.load(libname)

        is.loaded(symbol)
        symbol.C(name)
        symbol.For(name)

   AArrgguummeennttss::

    libname: a character string giving the pathname to a DLL.

     symbol: a character string giving a symbol name.

       name: a character string giving either the name of a C
             function or Fortran subroutine.

   VVaalluuee::

        The function `dyn.load' is used for its side effect
        which links the specified shared library to the execut-
        ing R image.  Calls to `.C' and `.Fortran' can then be
        used to execute C functions or Fortran subroutines con-
        tained in the library.

   NNoottee::

        The creation of shared libraries the runtime linking of
        them into executing programs is very platform depen-
        dent.  In recent years there has been some simplifica-
        tion in the process because the C subroutine call
        `dlopen' has become the standard for doing this under
        Unix.  `dyn.load' uses the `dlopen' mechanism and
        should work on all platforms which support it.

        The original code for loading DLLs in UNIX was provided
        by Heiner Schwarte.  The compatibility code for HP-UX
        was provided by Luke Tierney.

   SSeeee AAllssoo::

        `.C', `.Fortran'.

   EExxaammpplleess::

        is.loaded(symbol.For("hcass2")) #-> probably  FALSE
        library(mva)
        is.loaded(symbol.For("hcass2")) #-> TRUE

