[Rd] dyn.load and function calls without 'PACKAGE' argument

Duncan Temple Lang duncan at wald.ucdavis.edu
Fri Dec 8 18:15:48 CET 2006

Hash: SHA1

jhallman at frb.gov wrote:
> I'm writing a package that interfaces to the FAME database, via a
> library of compiled C routines accessible through a Linux .so file.  My
> .onLoad() function loads the .so like this:
> dyn.load("/opt/fame/timeiq/lib/linux_x86/libjchli.so", local = F)
> and after that I also load my own fame.so via
> library.dynam("fame", package = "fame")
> The code in fame.so uses functions found in libjchli.so, making the
> 'local = F' argument in dyn.load() necessary. 

Well, that is one approach.
A more  regular and in most senses "better" approach is to
have your fame.so link against libjchli.so when creating
the fame.so DLL/SO.  Then you don't have to pollute the
global symbol table for the process with libjchli.so
and you can use the PACKAGE argument.

That said, the PACKAGE argument is not necessary if you use
a NAMESPACE file for the package.
Load the fame.so with useDynLib() in the NAMESPACE file
and not library.dynam()

And if you explicitly list the routines you want to use
in the useDynLib() call, you can refer to them as
  .Call(foo, ...)

with no quotes, no PACKAGE and you will be able to handle
multiple versions and provide aliases for the routine names.

> But since Fame symbols
> are found in libjchli.so, which is NOT part of my package, I can't, for
> example, do this:
> .C("cfmfin", status = integer(1), PACKAGE = "fame")
> since the PACKAGE argument tells R to look only in fame.so for symbols.
> Instead, I have to do it without specifying 'PACKAGE', i.e., 
> .C("cfmfin", status = integer(1))
> This works, but 'R CMD check' complains: 
> "Foreign function calls without 'PACKAGE' argument:"
> followed by a list of the functions called from libjchli.so.
> Is there a way to make R CMD check happy here?
> Jeff
> ______________________________________________
> R-devel at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-devel

- --
Duncan Temple Lang                    duncan at wald.ucdavis.edu
Department of Statistics              work:  (530) 752-4782
4210 Mathematical Sciences Building   fax:   (530) 752-7099
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University of California at Davis
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