[Info-vax] What is a section file? How is it helpful? Is a TPU$SECTION file a section file?

[Richard Maher]

On 3/09/2022 8:05 am, Stephen Hoffman wrote:
> On 2022-09-02 14:38:27 +0000, Hein RMS van den Heuvel said:
> 
>> On Thursday, September 1, 2022 at 8:37:00 PM UTC-4, Arne Vajhøj
>> wrote:
>>> On 9/1/2022 12:53 PM, Stephen Hoffman wrote:
>> 
>>>> It's a section of virtual memory with backing (and sharable) 
>>>> storage, with the salient difference being whether it uses
>>>> static mapping—Fortran, BASIC, C, etc., common storage
>>>> involving the linker—or use dynamic mapping—run-time calls to
>>>> $crmpsc, etc.
>>> ????
>>> 
>>> A Fortran common block does not share data between processes and
>>> does not map data to disk.
>> 
>> I posted a knee-jerk reaction after reading that first line, which
>> I 'deleted' but may have made it out there.
>> 
>> It suggested to Arne to  please read more carefully (and more
>> manuals) as Stephen wrote "involving the linker". A Fortran common
>> block _can_ be used to share data between processes and _can_ map
>> to disk.
> 
> Which are the two most common reasons I've found a Fortran or BASIC 
> COMMON useful. Pun intended.
> 
> Other reasons can include the creation of a more perfectly-convoluted
>  build procedure, or to make OpenVMS upgrades more problematic, or to
> add fodder for data synchronization and data race conditions, of
> course. 😜
> 
> Slightly more seriously, I prefer to avoid using a COMMON, due to 
> position-dependence and app update issues encountered over the years.
>  But when working in Fortran or BASIC, some trade-offs can be
> necessary.
> 
>> It just requires a good bit of linker involvement, more than most 
>> remember how to do.
> 
> Or more linker involvement than most would prefer to remember.
> 
> 
> 
> 

And COBOL EXTERNAL