[gdal-dev] Is writing/reading a VRTs an atomic operation?

[Even Rouault]

On jeudi 6 décembre 2018 13:59:07 CET Pablo Sanfilippo wrote:
> Hello!
> 
> I'm building an application in which I will have multiple concurrent
> process reading and writing to a VRT file. The writers are just multiple
> instances of the same process that create a .vrt off a list of tiffs in a
> folder. The writer process implement file locking, so I'm sure no two
> processes will try to write the .vrt at the same time. But the readers
> (which are gdal_translate calls that use the .vrt as input) don't lock the
> .vrt so they can be ran at the same time. I can see a race condition
> happening if gdalbuildvrt overwrites the file when some gdal_translate is
> opening it. So, if I'm understanding this correctly, the question boils
> down to: Is the read call that gdal_translate makes when reading a vrt file
> atomic? And is the write call that gdalbuildvrt makes when writing the file
> atomic?

Much likely not. At least there's no effort in the code to make read/write 
atomic.

Even

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