[Rd] fortan common block

Barry Rowlingson b.rowlingson at lancaster.ac.uk
Sun May 8 09:43:31 CEST 2011

On Fri, May 6, 2011 at 4:04 PM, Paul Gilbert
<pgilbert at bank-banque-canada.ca> wrote:
> Is it possible in R to call a fortran routine that sets variables in a common block and expect the values to persist when a call is made from R to a second routine that uses the common block?
> If not (as I suspect),  is it possible to use a common block in a group of routines that are used together, for as long the routines do not return to R?

Simple test seems to confirm it. Here's some 'tran with a setter and a getter:


      subroutine bar(n)
      common /c/ i

      subroutine geti(j)
      common /c/ i
      j = i

R CMD SHLIB comchk.f
 > dyn.load("comchk.so")

 > .Fortran("bar",as.integer(9))
 [1] 9

 > .Fortran("geti",as.integer(-1))
 [1] 9


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