How do you tell how much disk free is remaining

[Jiro Nakamura]

A question to you NeXT and UNIX wizards -
	How does one tell how much disk space one has on any  
particular volume? In other words, how does "df" work? The mntent  
doesn't give much information about the mounted entry.....
	This is for a NeXT (BSD4.3) system, BTW.
	What I want/have to do is to do some space checking before my  
application saves to make sure there is enough space to safe the  
document on. I could always run a "system" call, but this is  
wasteful, to say the least......

	- jiro nakamura
	jiro at shaman.com

ps. Replies via e-mail, s'il vous plait. :-)