Examples

• A C function is provided to add together two real numbers. The interface.ccl should read

      CCTK_REAL FUNCTION SumStuff(CCTK_REAL IN x, CCTK_REAL IN y)
      PROVIDES FUNCTION SumStuff WITH AddItUp LANGUAGE C
      USES FUNCTION SumStuff
  

• A Fortran function is provided to invert a real number. The interface.ccl should read

      SUBROUTINE Invert(CCTK_REAL INOUT x)
      PROVIDES FUNCTION Invert WITH FindInverse LANGUAGE Fortran
      USES FUNCTION Invert
  

  Note that SUBROUTINE has the same meaning as void FUNCTION.

• A Fortran function is provided to integrate any function over an interval. The interface.ccl should read

      CCTK_REAL Integrate(CCTK_REAL CCTK_FPOINTER  func(CCTK_REAL IN x), \
                          CCTK_REAL IN xmin, CCTK_REAL IN xmax)
      PROVIDES FUNCTION Integrate WITH SimpsonsRule LANGUAGE Fortran
      USES FUNCTION Integrate