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Controlling the order of useDynLib lines in NAMESPACE with roxygen2

I am working on a R package that uses an external 3rd party dll to load data. I have written wrapper functions to that external dll that I can call with .C()

Assume that my package is called mypackage and the external is called xternal.dll. It seems that to load the mypackage.dll that is generated during compilation it is necessary that external.dll is loaded first. I am using roxygen2 to manage the NAMESPACE file, and I have used the #' @useDynLib tags. Unfortunately when roxygen2 writes the NAMESPACE file it adds the useDynLib calls in the lexical order of the shared object being called like A-Z, a-z.

Is there a way to control the order of the useDynLib in the namespace by roxygen2?

So far I have found the follwing solutions and neither of them seems to be particularly compelling:

  • Renaming my package to be lexically ordered after the external dll.

  • Managing the NAMESPACE file manually.

Example: The function foo.R:

#' @export
#' @useDynLib xternal
#' @useDynLib mypackage
foo <- function(){
  return(FALSE)
}

results in the NAMESPACE after calling devtools::document():

# Generated by roxygen2: do not edit by hand

export(foo)
useDynLib(mypackage)
useDynLib(xternal)

The package would fail to load, however if I manually swap the two useDynLib lines the package installs and works fine.

Solution

  • After a very helpful hint received on GitHub: The solution is to use the @rawNamespace tag, that writes a verbatim line into the NAMESPACE file:

    foo.R:

    #' @export
#' @rawNamespace useDynLib(xternal); useDynLib(mypackage)
foo <- function(){
  return(FALSE)
}

    results in a NAMESPACE file:

    # Generated by roxygen2: do not edit by hand

export(foo)
useDynLib(xternal); useDynLib(mypackage)

    and the shared objects are loaded in the correct order.