OS X: Generate core dump without bringing down the process?

Question

I know how to generate a core dump on OS X when a process crashes, but what I really need to do is attach to a process, generate a core dump, then resume that process (without killing it).

A long time ago (maybe a year and a half ago) I had C code that would do this... It used the OS X kernel libraries to connect to a process, read all of its thread states and memory, and write that into a Mach-O file on disk. This worked great (and it's exactly what I'm looking for), but now I can't seem to find that code for the life of me. I seem to recall that code was related somewhat to the OS X system internals book, but that's just a vague recollection.

Does anyone know the code I'm talking about and could point me at it? If not does anyone know a good way of doing this preferably with some example code?

Edit: Here is the answer.

Information: http://osxbook.com/book/bonus/chapter8/core/

Program that will do it for you: http://osxbook.com/book/bonus/chapter8/core/download/gcore-1.3.tar.gz