From: David Simas <dsimas@...>
Date: 2007-04-12T10:07:52+09:00
Subject: A C++ reference in a Ruby extension



I'm trying to write an extension to access some C++ libraries from
Ruby (1.8.4).  One of the C++ functions uses a reference to pass
a value back to the caller as a side effect:

   ErrorHandle* DetectInvisibleWatermark(const char *inputfilename,
					const char *wmfilename,
					float horizOffset,
					float vertOffset,
					float lowPassFilterFactor,
			      	 	float &modulationStrength,
					const char *key, const char *seed,
					const char *outfilename);

(N.B.: "float &modulationStrength")

Any suggestions on how to handle this reference in an extension?
I don't have the C++ sources, just libraries and header files.

Thanks,

DGS