[GRASSLIST:5846] Re: 2GB+ in Grass 6.0

[Maciek Sieczka]

From: "Glynn Clements" <glynn at gclements.plus.com>

> M-D$B_S(Bis Narti-B$B%1(Bs wrote:-A
>
>> > > Is it possible to load a 4.1 GB GeoTiff DEM into Grass 6.0 location?
>> > > I'm
>> > > getting "file size limit exceeded". Please help!
>> >
>> >  GRASS 6.0 supports reading and writing large files (> 2GB) if it is
>> > possible in your operating system. If you compile with
>> > -D_FILE_OFFSET_BITS=64, you should be able to have raster maps which
>> > are larger than 2Gb.
>>
>> How can this be enabled in ./configure? Or it is autodetected?
>
> The configure script automatically imports several common make
> variables from the environment, including CFLAGS, so you can use e.g.:
>
> CFLAGS='-g -D_FILE_OFFSET_BITS=64' ./configure ...
>
> Note that this will enable transparent large file support throughout
> of GRASS. However, only the core raster I/O functions have actually
> been specifically updated to support large files. Other parts of GRASS
> may fail in unpredictable ways if they try to access large files.
>
> Also, if you are using r.in.gdal to import the DEM, the GDAL library
> must have been built with large file support.
>
>> How can I check is my Grass compiled with this -Dblahblah option?
>
> Try running "nm -D /usr/local/grass-6.0.cvs/lib/libgrass_gis.so" (or
> whatever libgrass_gis is called on your system); if you see references
> to open64, lseek64 etc in the output, it was built with transparent
> large file support.

Thanks for detailed explanation Glynn. Wouldn't it be usefull for everybody 
if these remarks went to INSTALL file?

Maciek