The Problem still is there.
The empty() Command delivers a false while the Value itself can be compared with 0.
The empty() command obviously has a bug.
Here's the Code again.

clear
local a, b, c, d,x
a= -1
b= -0.1
c= 1
d= 0.1
x= a+b+c+d
? empty(x)
? x=0 &&This should also deliver a ".f." but it gives us a .t.

I think Microsoft should repair this. I understand the floating point, but I never suspected it in any command from FoxPro.

Here's a workaround code. But I think we could instanciate every FoxPro command like this one if we can not dely on the behavior. Also this slows down our programs a little bit.

*proc_empty.prg
lparameters lvValue
if type("lvValue")="N"
return lvValue=0
else
return empty(lvValue)
endif