[postgis-devel] PgSQL 12 and -Werror=vla

[Even Rouault]

On mercredi 31 octobre 2018 14:25:34 CET Paul Ramsey wrote:
> Looks like it was Andres, about two months ago, during the switch to
> "modern" C99
> 
> https://github.com/postgres/postgres/blame/696b0c5fd0a8765fe6dfd075a30be06b4
> 48fd615/configure.in#L488
> 
> Wikipedia commentary :)
> 
> https://en.wikipedia.org/wiki/Variable-length_array#C99

Beyond Linus' arguments about speed and code size which aren't really relevant 
here unless you're counting the number of CPU cycles, looking a bit at the 
code for the below cases, the use of VLAs seems inappropriate as the size 
argument could be pretty huge, being the number of points of the input 
geometries. Surprising that nobody hasn't come up yet with gigantic geometries 
that would blow up the stack of the process ( typically the default stack size 
of a Linux process is 8 MB, so a geometry with ~ 262 000 points would blow the 
stack). I wouldn't call fixing that bikeshedding.

Even

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