Re: Proposal: Add a callback data parameter to GetNamedDSMSegment

On Thu, Dec 04, 2025 at 05:40:21PM +0000, Zsolt Parragi wrote:
>> wouldn't the above be sufficient to create a DSM segment containing
>> a flexible array?
> 
> Yes, it creates it, but can I initialize it properly in
> foo_init_state? How can I set the size member to the proper array
> size, and how can I zero-initialize the array with the correct length
> in it? What I can do currently is:
> 
> 1. create the lwlock and set size to 0 in foo_init_state
> 2. take the lwlock after GetNamedDSMSegment returns
> 3. if size is 0 set it properly and zero-initialize the array
> 
> That's why I said that there is a workaround, but it would be nicer if
> I could do it properly in the init callback, by passing the array size
> as a parameter to it.

So, it seems like we've established at least 2 potential use-cases for this
argument (tranche name and flexible arrays).  And the amount of extension
breakage doesn't seem too bad either.  IMHO it'd be reasonable to proceed
with this change.

-- 
nathan