Getting double* from NumPy array?

[Ted Drain]

I have some existing C/C++ code that can accept a double array ( int len,
and double* ptr) to do some processing.  I want to allow users to create
arrays in python using NumPy and then provide an interface to pass these
arrays to my C/C++ code.  

Assuming a 1-dimensional NumPy array, is there an easy way to extract a
pointer to a double and length from the python object?  The C/C++ isn't
going to change the object so I'd prefer not to make a copy of it.

Thanks
Ted

-- 
Ted Drain   Jet Propulsion Laboratory    Ted.Drain at jpl.nasa.gov