memory checking functions

[bright@ENH.NIST.GOV]

Are there functions out there that return the amount of memory available so
that functions can warn the user when it gets low?  Something akin to
(room) that returns values rather than printing to *standard-output*?

Thanks
--Dave
David S. Bright                        bright@enh.nist.gov  
Microanalysis Research Group                                   
National Institute of Standards & Technology (NBS)
Gaithersburg, MD 20899                                           
USA
301-975-3911