[gdal-dev] Unable to get features from OpenFileGDB data source

[Nik Sands]

Hi GDAL devs,

I'm trying to support ESRI File Geodatabase support (read-only) in my iOS app and have recently got GDAL 1.11.0 compiled and running in the app for its new OpenFileGDB driver.  However, I've been unable to extract features from GDBs using the exact same code that works fine for other formats/drivers.

An extract of the code in question is:

------------------------
	ds = OGROpen(path, FALSE, NULL);
	layerCount = OGR_DS_GetLayerCount(ds);
	
	for ( int i = 0; i < layerCount; i++ )
	{
		OGRLayerH sourceLayer = OGR_DS_GetLayer(ds, i);
		int sourceFeatureCount = OGR_L_GetFeatureCount(sourceLayer, YES);

		for ( long j = 0; j < sourceFeatureCount; j++ )
		{
			OGRFeatureH sourceFeature = OGR_L_GetFeature(sourceLayer, j);

			if ( ! sourceFeature )
				NSLog(@"Failed to get feature at index '%ld' from layer at index '%d'!", j, i);
------------------------

The NSLog line is always run for my GDB data sources but never for data sources of other formats.  So for GDB data sources 'sourceFeature' is always NULL and of course this causes all subsequent OGR functions to which 'sourceFeature' is passed to fail with errors like:

	ERROR 10: Pointer 'hFeat' is NULL in 'OGR_...'.

Using the CLI utility 'ogrinfo' (different build of GDAL) on the same datasource works fine showing all the features are there as expected and it works fine in ESRI ArcGIS.  And the fact that it gets into the second 'for' loop at all indicates that there are features there, and yet it cannot get the feature at index '0'.

The File Geodatabase datasource can be downloaded for testing from:

	https://dl.dropboxusercontent.com/u/12436846/Bandicoots.gdb.zip

Can anybody advise me on how I should trouble shoot this further, or how the problem can be resolved?

Cheers,
Nik.