> -----Original Message-----
> From: Buck Calabro [SMTP:mcalabro@commsoft.net]
> Sent: Tuesday, February 24, 1998 3:36 PM
> To: MIDRANGE-L@midrange.com
> Subject: Re[2]: RPG on other platforms...
>
>
> >Jim Welsh wrote:
> >
> > I've been asked by my employer to do some research on the effects of
> > running an RPG III
> > program on platforms other than the AS400.
> >
> >As far as your information on reentrant goes: All programs on the
> AS/400 are
> >reentrant by nature. There is no special coding required. The
> compiler creates
> >an object which contains the instruction set and base memory offset
> to the data.
> >Each user upon calling the program will be assigned a base memory
> address for
> >their data and control information to track the current instruction
> being
> >executed. So A + B = C turns into OffsetForA + OffsetForB =
> OffsetForC and is
> >executed as (UserBaseAddress+OffsetForA) +
> (UserBaseAddress+OffsetForB) =
> >(UserBaseAddress+OffsetForC).
>
> Kind of an interesting way to look at the PAG, but it gets the idea
> across!
>
> >Special coding was required for the S/36 MRT programs which were a
> crude attempt
> >at reentrant concept: one copy of instructions, many copies of data.
>
> All too true!
> But is Jim asking about re-entrancy or recursiveness?
>
> Re-entry means that no matter how many people are using a program,
> only one copy is active in memory at once. Recursiveness means that
> RPG program A can call RPG program B who can call RPG program A
> again. That's not allowed in OPM RPG (sadly, I haven't checked for
> ILE.)
>
[Stone, Brad V (TC)] But for each job there would be a different copy
in memory for programs. Display files, not so. Right?
> Once Program A is in the job's call stack, it can't be CALLed again
> or you'll get:
> Message ID . . . . . . : RPG8888 Severity . . . . . . . : 99
>
> Message type . . . . . : Inquiry
>
> Date sent . . . . . . : 02/24/98 Time sent . . . . . . :
> 15:36:19
>
>
> Message . . . . : CMD called itself recursively (C S).
>
> Cause . . . . . : The RPG program CMD called itself or another
> program which
> then called program CMD.
>
> Recovery . . . : Enter C to cancel, or S to obtain a system dump.
>
> Possible choices for replying to message . . . . . . . . . . . . . . .
> :
> C -- Cancel
>
> S -- Obtain system dump
>
>
> Buck Calabro
> Commsoft, Albany, NY
>
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[Stone, Brad V (TC)]
Bradley V. Stone
bvstone@taylorcorp.com
http://prairie.lakes.com/~bvstone/
"People train don't run out of Wicheta... Lessn' you're a hog, or a
cattle. People train runs out of Stubville."
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| This is the Midrange System Mailing List!
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