[Gdal-dev] problem about "RasterIO"

Frank Warmerdam warmerdam at pobox.com
Mon Oct 9 13:17:59 EDT 2006

qq wrote:
> HI:
>   I tried to read a .tif file with data type of "GDT_Byte" using the 
> method of "RasterIO". It did well without problem. But When I tied to 
> read a .tif file with data type of "GDT_Int32", it did't work.  My code 
> is here:
> if (RasterBand->GetRasterDataType() == GDT_Int32){
>   LONG* pData;
>   pData = (LONG*) CPLMalloc(sizeof(LONG)*nXSize*nYSize);
>   RasterBand->RasterIO( GF_Read, 0, 0, nXSize, nYSize, pData, nXSize, 
> nYSize,   GDT_Int32, 0, 0 );  
>   }
> The pData is NULL. And the image data can't be read from the file. Would 
> anyone tell what is the wrong? Thanks !


It sounds like the buffer allocation is failing because of a lack
of memory.  Is your file large?

Best regards,
I set the clouds in motion - turn up   | Frank Warmerdam, warmerdam at pobox.com
light and sound - activate the windows | http://pobox.com/~warmerdam
and watch the world go round - Rush    | President OSGeo, http://osgeo.org

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