[R] compile Fortran code which calls C subroutine

[Zhijin Wu]

      I used "R CMD SHLIB" to compile the fortran filename.f file and the
    filename.so is generated. But since in filename.f it calls
    another subroutine written in C, i had problem in "dyn.load" because it
    could not find the C subroutine. 
     I have the .c file but don't know how to tell R about it.
      How should I compile when I want to call the fortran function in R 
which  calls (FORTRAN-callable) C-code?
      Thanks a lot!
    best regards,
    Zhijin