module olp
   implicit none
   public :: OLP_Start, OLP_EvalSubProcess2, OLP_SetParameter
   public :: OLP_Info, OLP_Polvec
   
contains

subroutine OLP_Start(contract_file_name,ierr) &
 & bind(C,name="OLP_Start")
   use, intrinsic :: iso_c_binding
   implicit none
   character(kind=c_char,len=1), intent(in) :: contract_file_name
   integer(kind=c_int), intent(out) :: ierr
   
  interface
     function strlen(s) bind(C,name='strlen')
       use, intrinsic :: iso_c_binding
       implicit none
       character(kind=c_char,len=1), intent(in) :: s
       integer(kind=c_int) :: strlen
     end function strlen
  end interface
  
    
   ! ...
   ! open( ... , file=contract_file_name(1:strlen(l)), ...) 
   ! ...
   
end subroutine


subroutine OLP_SetParameter(variable_name, real_part, complex_part, success) &
 & bind(C,name="OLP_SetParameter") 
   use, intrinsic :: iso_c_binding
   implicit none
   character(kind=c_char,len=1), intent(in) :: variable_name
   real(kind=c_double), intent(in) :: real_part, complex_part
   integer(kind=c_int), intent(out) :: success

   !....
end subroutine

subroutine OLP_EvalSubProcess2(label, momenta, mu, res, acc) &
   & bind(C,name="OLP_EvalSubProcess2")
   use, intrinsic :: iso_c_binding
   implicit none
   integer(kind=c_int), intent(in) :: label
   real(kind=c_double), intent(in) :: mu
   real(kind=c_double), dimension(50), intent(in) :: momenta
   real(kind=c_double), dimension(60), intent(out) :: res
   real(kind=c_double), dimension(1), intent(out) :: acc

    !....
end subroutine OLP_EvalSubProcess2

subroutine OLP_Info(olp_name, olp_version, cite_message) &
 & bind(C,name="OLP_Info")
   use, intrinsic :: iso_c_binding
   implicit none
   character(kind=c_char,len=1), intent(out) :: olp_name
   character(kind=c_char,len=1), intent(out) :: olp_version
   character(kind=c_char,len=1), intent(out) :: cite_message
   
   ! ...
   
end subroutine OLP_Info

subroutine OLP_Polvec(p, q, eps) &
   & bind(C,name="OLP_PolVec")
   use, intrinsic :: iso_c_binding
   implicit none
   real(ki), dimension(4), intent(in) :: p,q
   real(ki), dimension(8), intent(out) :: eps

    !.... optional
    
end subroutine OLP_Polvec

end module olp