Function Argument Evaluation

[Jonathan Gingerich]

First a sincere thanks to everyone trying to help.  Second, a reminder that
precision and meticulousness can often be mistaken for pedantry and rudeness,
especially if people are not addressing the central issue.  Both Christopher
and I realize the assignment may cause a type conversion, and we both realize
different sequences of operations can have different results.  Thank you.  You
can stop posting such examples now.

I originally wanted to satisfy my own curiosity about this and pointed out
that the answers so far were not in agreement.  I still have a question so
let me rephrase it:

Is there any situation where the value stored at l can change before (l=r)
is evaluated but after the assignment, without causing the program to be
undefined?
If so, is the value of (l=r) nonetheless restricted to the value of l 
_immediately_ after the assignment?

Jon.