RE: Prototyping printf()

[Joel Fritz <JFritz@xxxxxxxxxxxxxxxx>]

I think we're in agreement, and maybe I wasn't clear.  It's the passing by
value that highlights the string variable's type ambiguity.  C was designed
so that a function could return only one value. <g>

I think it would be really cool if RPG could support descriptors in the way
printf() does. RPG also has the problem of a requiring a finite number of
arguments for a procedure. 


> -----Original Message-----
> From: Simon Coulter [mailto:shc@flybynight.com.au]
> Sent: Monday, September 25, 2000 6:50 PM
> To: RPG400-L@midrange.com
> Subject: Re: Prototyping printf()
> 
> 
> �
> Hello Joel,
> 
> You wrote:
> >I may be missing something, but I think it hinges on the 
> conveniently(?)
> >ambiguous way strings work in C  and printf()'s being a 
> function with a
> >variable argument list.  Even though strings are pointers in 
> C, there are
> >situations, like printf(), where you can use them like the 
> numeric data
> >types. 
> 
> I think you are missing that fact the C compiler is not just 
> passing pointers.  If it 
> were then an RPG definition that also passed pointers would 
> work.  The trick would be in 
> whether the address of the pointer was passed or the value of 
> the pointer.  However the C 
> compiler is passing the list of variables according to their 
> type and also useing the 
> normal C behaviour of passing by value.  So variable argument 
> lists can be handled by 
> passing everything by the value of the vatiable.  RPG 
> normally passes by reference 
> therefore we need to use a prototype to override that 
> behaviour and then RPG requires us 
> to specify the data type and that's where the problem lies.
> 
> >I would be surprised and gratified if there were a way to do 
> it, but I think
> >you've hit on something where there is no common ground 
> between the two
> >languagages.  
> 
> Funny about that!
> 
> >BTW, how are you using printf() in RPG?  Is it CGI?   
> 
> No.  It was just an experiment.
> 
> Regards,
> Simon Coulter.
> 
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