Re: "out" parameters

["Robert I. Eachus" <rieachus@comcast.net>]

Keith Thompson wrote:
> Ludovic Brenta <ludovic.brenta@insalien.org> writes:
> [...]
> 
>>Besides by-copy and by-reference, there is also the possibility of
>>passing parameters in processor registers.
> 
> 
> Isn't that just a special case of by-copy?

Technically,  no.  An argument can be passed by reference in a register, 
even though the reference is implicit in the code.  For example you 
could have a bit array in a register, and pass the index of the bit that 
was a parameter.

The only reason this matters is that there are hardware registers which 
may be implicit or explicit arguments to OS routines.  The semantics are 
by reference, even though the registers are defined by the hardware.

-- 

                                           Robert I. Eachus

"The terrorists rejoice in the killing of the innocent, and have 
promised similar violence against Americans, against all free peoples, 
and against any Muslims who reject their ideology of murder. Their 
barbarism cannot be appeased, and their hatred cannot be satisfied. 
There's only one way to deal with terror: We must confront the enemy and 
stay on the offensive until these killers are defeated." -- George W. Bush