On Oct 20, 10:51 pm, Tommy Grav <tg...@pha.jhu.edu> wrote:
> I have created a binary file that saves this struct from some C code:
>
> struct recOneData {
> char label[3][84];
> char constName[400][6];
> double timeData[3];
> long int numConst;
> double AU;
> double EMRAT;
> long int coeffPtr[12][3];
> long int DENUM;
> long int libratPtr[3];
> };
>
> I try to read this file with python (ActiveState 2.6.3 on x86_64 Mac
> OS X 10.6.1) using the
> code below the hdrData and constNData are fine, while from the
> timeData onwards there
> are obvious problems. The code below works fine for a 32bit binary
> read with i386 python
> 2.5.2. Does anyone know what the proper format of a C double and long
> int is for a x86_64
> binary?
As others have said, it depends on the platform. But on OS X 10.6,
and on most 64-bit Linuxes that I've met, I'm fairly sure that
sizeof(long int) == sizeof(double) == 8. In contrast, 64-bit
Windows on the same hardware will probably have sizeof(long int) == 4.
>
> def read_header(cls):
> hdrData = "84s"*3
> constNData = "6s"*400
I'm confused: why is this not "400s"*6 rather than "6s"*400?
Doesn't constName[400][6] mean 6 lots of constName[400]?
Similarly for "84s"*3. This might be making a difference to
the padding.
[...]
--
Mark
--
http://mail.python.org/mailman/listinfo/python-list
