Re: sizeof (struct) differs from Windows and Linux. How can I fix this?

[Vladislav Grinchenko <3rdshift comcast net>]

Edward,

you might want to consider XDR as persistent binary format.

-Vlad

On Wed, 2004-12-29 at 12:57, edward hage wrote:
> I store data of several large arrays of structs in a binairy file. There are 2 kinds of 
> structs:
> Struct 1 has 3 x gchar[70] and 16 doubles and one guint[12].
> Struct 2 has 2 x gchar[70] and 4 doubles.
>
> On linux and Windows the following results are the same:
> sizeof(double)=sizof(gdouble) = 8
> sizeof(guint)=4
> sizof(gchar)=1
>
> So netto the size of struct1 should be : 386 and struct 2 172.
>
> Now on Linux the size of the structs are resp. : 388 and 172.
>
> And on Windows XP (cross-compile mingw on Linux): 392 and 176.
>
> Now I don't mind that they are slightly bigger than the sum of their elements, but the 
> problem is that I can not load the library in Windows (just ported that, loading on Linux 
> is okay because the binairy file also saves them with size 388 and 172).
>
> I have the following questions:
> 1) Should the struct be as large as their elements or does the definition of the struct 
> itself needs some space (and if so, why not for the 172 byte - struct)?
> 2) How can I read the file in Windows correctly?
>
> Because the sum of the elements on Linux and Windows is the same I have an idea that 
> guint16 and its friends (always the same size) won't help me in my case. It's the struct 
> that is different! (I think ...?)
>
>
> Help is very much appreciated.
> Edward Hage
>
>
>
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-- 
_____________________________________________________________
Vladislav Grinchenko       http://home.comcast.net/~3rdshift/
                                 e-mail: 3rdshift comcast net
                                                   
      Focus on quality, and productivity will follow.
_____________________________________________________________