[Info-vax] Creating an open source version of VMS, was: Re: OpenVMS Hobbyist Notification

[VAXman- at SendSpamHere.ORG]

In article <r4c3bd$8fa$1 at dont-email.me>, Simon Clubley <clubley at remove_me.eisner.decus.org-Earth.UFP> writes:
>On 2020-03-11, VAXman-  @SendSpamHere.ORG <VAXman- at SendSpamHere.ORG> wrote:
>>
>> In article <r4bfgn$1ec9$1 at gioia.aioe.org>, =?UTF-8?Q?Arne_Vajh=c3=b8j?= <arne at vajhoej.dk> writes:
>>>On 3/11/2020 9:33 AM, Simon Clubley wrote:
>>>> On 2020-03-10, Arne Vajhøj <arne at vajhoej.dk> wrote:
>>>>> It would look like VMS, but because of all the
>>>>> "improvements" then a lot of existing VMS stuff would
>>>>> not run as expected.
>>>> 
>>>> That depends on how much existing VMS application code bypasses the
>>>> documented APIs and tries using the private/undocumented memory
>>>> locations and functions.
>>>
>>>They don't even need to use that any private/undocumented for
>>>your approach to break things.
>>>
>>>Trivial example:
>>>* COM file use F$GETJPI to retrieve PID and create a file with
>>>   that in file name
>>>* COM file run EXE
>>>* EXE use LIB$GETJPI to retrieve PID and read the file
>>>
>>>Both F$GETJPI and LIB$GETJPI are public well documented,
>>>but if you change DCL from running EXE in same process to
>>>run in different process, then the above stop working.
>>
>> That's just short-sighted programming.
>>
>
>Maybe, but I could see it being a problem to a few people.
>
>Two possible ways around this:
>
>1) The returned PID is actually that of the parent shell PID and you
>use another value (such as REAL_PID or MY_PID) to get your own PID.
>
>2) You add another option, called SPID or similar, to get the parent
>shell PID and change your command procedure to use that instead on
>the rare occasion you need something like this.
>
>I do not like option 1 as it is a hack and option 2 feels way cleaner.
>Option 2 is also the same as the $$ syntax in bash.

I prefer the option of understand the OS and the APIs provided.  How the
FiretrUCK would you do it on unix with everything being is own process?

-- 
VAXman- A Bored Certified VMS Kernel Mode Hacker    VAXman(at)TMESIS(dot)ORG

I speak to machines with the voice of humanity.