En Tue, 20 Oct 2009 18:51:21 -0300, Tommy Grav <tg...@pha.jhu.edu>
escribió:
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?
I'd start comparing at least both struct sizes to see if they match. Then,
at the C side determine offset and size of each member using macros like
these:
#define COUNT_OF(_array) (sizeof(_array)/sizeof(*(_array)))
#define OFFSET_OF(_structure, _member) ((size_t)&(((_structure
*)0)->_member))
#define SIZE_OF(_structure, _member) (sizeof((((_structure *)0)->_member)))
and then add padding bytes ('x') to the struct definition in Python to
match those offsets (and probably use '=' for standard sizes).
--
Gabriel Genellina
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