On 8 Sep 2006, at 15:27, Roger Bivand wrote:
> On Fri, 8 Sep 2006, Tim Keitt wrote:
>
>> One possibility is that the size of the GDAL data type is not the
>> same
>> as the size of the R data type. This will definitely cause
>> problems as
>> allocation is done by R and the pointer is cast to void when
>> passed to
>> GDAL. My original C++ code simply assumes that both are 32-bit (or at
>> least equivalent size), but things will break if they are different.
>> (Roger -- you probably noticed the "fix me!" comments to myself in
>> there -- that was what I was talking about.)
>
> (about line 750 in src/gdal-bindings.cpp)
>
> Yes, but this is an example that is run very often on i386 at
> least, so
> I'm not sure why it should show up now on an other-endian platform?
> GDAL
> knows about endian-ness, doesn't it? Without access to the specific
> platform and build train, it would be difficult to debug?
I can certainly provide access to a test system and/or follow
instructions for testing if that would help. If you'll be in
Lausanne next week, we could discuss this more there.
> What else do we
> know about the platform? Is a G5 64-bit (ie. how big is an int)?
Yes, G5 is 64 bit, but if I understand correctly, one needs to
"request" this capability when compiling. I see that sizeof(int)
returns a value of 4 if I run it on a G5 or a G4 (which is not 64
bit)...
Actually, looking a little deeper and reading the gcc man page, if I
just compile with defaults, int is 4 and long is 4, but if I use -m64
when compiling, int is still 4 but long is 8.
The powerpc build uses the same flags as the i386 for 32/64 (from man
gcc):
-m32
-m64
Generate code for 32-bit or 64-bit environments of Darwin
and SVR4
targets (including GNU/Linux). The 32-bit environment
sets int,
long and pointer to 32 bits and generates code that runs
on any
PowerPC variant. The 64-bit environment sets int to 32
bits and
long and pointer to 64 bits, and generates code for
PowerPC64, as
for -mpowerpc64.
Hope that helps,
Scott
------
Scott W. Mitchell [EMAIL PROTECTED]
Geomatics and Landscape Ecology Research Laboratory
Department of Geography and Environmental Studies
Carleton University, B349 Loeb Building
Ottawa, ON Canada K1S 5B6
+1-613-520-2600 ext 2695
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