[Rd] question re: error message --- package error: "functionName" not resolved from current namespace

[Duncan Murdoch]

On 10/04/2013 2:25 PM, brian avants wrote:
> hi simon
>
> thank you for your questions ---- answers here:
>
> I won't answer your question directly but some suggestions:
> > a) does adding PACKAGE="ANTsR" to .Call change anything? (It should really
> > be there if you are using strings as names)
> >
>
> this does change things .... for instance, this works:
>
> library(ANTsR)
> filename<-getANTsRData('r16')
> .Call("antsImageRead", filename,'double',2) #  Succeeds!
> .Call("antsImageRead", filename,'double',2,PACKAGE=ANTsR) #  Fails!
> # Error in .Call("antsImageRead", filename, "double", 2, PACKAGE = "ANTsR")
> :
> #  "antsImageRead" not available for .Call() for package "ANTsR"

That makes it look as though it is finding that entry point somewhere 
other than in the ANTsR.{so|dll} file installed with the package.
>
> the problem is when we call this function:
>
> antsImageRead <- function( filename , dimension , pixeltype = "float" )
> {
>      rval <- (.Call("antsImageRead", filename, pixeltype, dimension))
>      return(rval)
> }

That's the one where you should be using the PACKAGE declaration.

>
> the we get the error   antsImageRead not resolved from current namespace ,
> e.g.:
>
> > antsImageRead(filename,2)
> Error in .Call("antsImageRead", filename, pixeltype, dimension) :
>    "antsImageRead" not resolved from current namespace (ANTsR)
> >
>
>
> b) you may want to consider use the more efficient registration - either
> > explicit or in NAMESPACE - so in your case you could use
> > NAMESPACE: useDynLib(ANTsR, antsImageRead, ...)
> > foo.R: .Call(antsImageRead, ...)
> >
>
> yes - we have all of our shared libraries registered in the NAMESPACE file
> e.g.
>
> useDynLib(libRantsImageRead)

But this doesn't register the entry point.  List it explicitly, and it 
will create an object called antsImageRead in the package namespace that 
has entry point information.

Duncan Murdoch
>
> etcetera ....
>
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>
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