Interlanguage Calls - Call-by-Reference Parameters

For call-by-reference (as in Fortran), the address of the parameter is passed in a register.

When passing parameters by reference, if you write C or C++ function that...

you want to call from a Fortran program, declare all parameters as pointers.
calls a program written in Fortran, all arguments must be pointers or scalars with the address operator.
you want to call from a Pascal program, declare as pointers all parameters that the Pascal program treats as reference parameters.
calls a program written in Pascal, all arguments corresponding to reference parameters must be pointers.