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

[Stephen Hoffman]

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.




-- 
Pure Personal Opinion | HoffmanLabs LLC