[gdal-dev] Gdal Asynchronous IO

Even Rouault even.rouault at mines-paris.org
Mon Mar 11 13:34:59 PDT 2013

Le lundi 11 mars 2013 21:21:50, Allen Kempe a écrit :
> In Rfc 24: GDAL Progressive Data Support it says that the metadata for a
> driver will specify metadata item "DCAP_ASYNCIO" as yes if the driver
> supports asynchronous IO. So, code like this should retrieve this option:
> const char* s_asyncio = drv->GetMetadataItem("DCAP_ASYNCIO");
> However, I have been unable to find any drivers that return "Yes".

Hum, grepping the GDAL code base, it seems that this metadata item has never 
been set in drivers implementing progressive rendering.

> So, is this the correct way to check whether a driver supports
> asynchronous io?
> Are there any drivers that currently support this besides Kadaku which I
> don't have?

"grep -r BeginAsyncReader frmts/" shows that the only drivers supporting async 
io are JPIPKAK and ECW (with SDK 4.x and later)

>     Allen Kempe
> http://acksoft.dyndns.biz/PictureGallery
> 298 W. Audubon Drive
> Shepherdsville, KY 40165
> +1 502 543-3438

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