[Info-vax] VMS process communication

[Arne Vajhøj]

On 3/22/2023 7:18 AM, Ian Miller wrote:
> On Tuesday, March 21, 2023 at 11:34:04 AM UTC, Arne Vajhøj wrote:
>> On 3/20/2023 5:37 AM, Andreas Gruhl wrote:
>>> Arne Vajhøj schrieb am Samstag, 18. März 2023 um 01:26:39 UTC+1:
>>>> On 3/16/2023 5:05 AM, Andreas Gruhl wrote:
>>>>> Arne Vajhøj schrieb am Donnerstag, 16. März 2023 um 01:47:31
>>>>> UTC+1:
>>>>>> On 3/10/2023 4:01 PM, Arne Vajhøj wrote:
>>>>>>> https://www.vajhoej.dk/arne/articles/vms64.html
>>>>>> 
>>>>>> Updated to version 1.0 based on comments.
>>>>> Small correction: PASCAL/USAGE=64BIT_TO_DESCR does NOT change
>>>>> the compiler's treatment of pointers. Interpreting pointers
>>>>> as unsigned values has to be provided by the programmer. The
>>>>> qualifier only allows for P2 structures to be used as actual
>>>>> routine parameters via descriptor, which otherwise would be
>>>>> flagged as a compile time error.
>>>> So it does not change the treatment of pointers.
>>>> 
>>>> It disables a compiler check.

>>> That's correct.
>> 
>> I have updated.

> On VMS E9.2-1 x86-64 all code by default is put into P2 by the linker
> but you can put /SEGMENT=CODE=P0 to stop that. I suspect this is
> going to cause some issues when porting.  For kernel mode code the
> recommendation is to change from locking specific parts of the code
> into the working set to locking the whole image as this works on I64
> and x86 VMS by calling LIB$LOCK_IMAGE.

So is a function pointer always 64 bit?

Arne