[Info-vax] Returning data from Cobol AST routine.

[Arne Vajhøj]

On 9/21/2021 9:46 PM, Dave Froble wrote:
> On 9/21/2021 5:13 PM, Jan-Erik Söderholm wrote:
>> But my guess is that, if you queue QIOs from multiple sources, the AST
>> routine must have some way to tell which source it was that trigged
>> the AST. Say you make (made up example, not part of our current target)
>> 10 QIO calls having the address of the same AST routine in the calls,
>> each QIO reading from its own TNA device, you need to know in the AST
>> routine which TNA device (like 10 different production machines) it
>> was that sent something.
> 
> That sounds like a real headache.  Perhaps event flags would help.  I 
> tend to avoid event flags.
> 
>> I have probably not read enough aboit AST and QUI calls yet...
> 
> ASTs can be fun.  I try to use them to set flags or cancel I/O. 
> Cancelling an I/O causes a completion of an async read.  I feel that if 
> I try to get "tricky", I'll outsmart myself,

That is why I suggested a message queue instead of mailboxes,
$QIO(W) and AST's.

Way less options for experiencing "unexpected features".

Arne