[gdal-dev] Thread safe?

[Even Rouault]

Le mercredi 11 janvier 2012 22:32:45, Billy Newman a écrit :
> I am using a third party lib (imageio-ext) to leverage gdal in java code.
> I have noticed that the imageio-ext folks have wrapped the gdal.Open(..)
> call in a synchronized method.  I am assuming this is to prevent
> imageio-ext users from hanging themselves with regard to thread safety.
> 
> I have looked at the gdal FAQ with regards to thread safety and the last
> release that it mentions additions is 1.3.0.
> 
> What is the current status of the 1.9.* build with regards to thread
> safety.

The following is still true : "In particular for the situation where many 
threads are reading from GDAL datasets at once should work as long as no two 
threads access the same  GDALDataset object at the same time. However, in this 
scenario, no threads can be writing to GDAL while others are reading or chaos 
may ensue. "

I believe most common GDAL drivers should be safe. That includes drivers that 
don't depend on third party librairies (the driver is self contained in GDAL 
source tree), and drivers that depend on "classic" third-party libraries (such 
as PNG, JPEG, GIF). For other third party libraries (netCDF, HDF4, HDF5, ...), 
this depends on whether they are thread-safe themselves. There's at least one 
driver that is known to be non thread-safe : GRIB.

> 
> Thanks,
> Billy
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