[fpc-pascal] Binary compatibility between Intel CPU and PowerPC CPU

[Gustavo Enrique Jimenez]

2008/9/16 Adriaan van Os <fpc at microbizz.nl>:
> Roland Turcan wrote:
>>
>> Hello FPC-Pascal users discussions!
>>
>> What is the best way to keep the binary compatibility among different
>> CPU architectures.
>>
>> I need to make our own database engine compatible and other binary
>> files, that user still can use our data from i386 or PowerPC computer.
>>
>> I really don't like the idea to change the order of all numeric
>> variables on PowerPC, because it costs time of CPU.
>>
>> There must be easier way how to keep the compatibility.
>>
>> Could you give me some hints for better solution.
>
> Whether you "like the idea" or not, the best way is as follows:
>
> - add a byte to the header of source data that indicates the endianness,
> high-endian for PowerPC, low-endian for i386
> - perform byte swapping if the endianness of source data is different from
> the endianness of the current CPU
>
> With "source data" I mean
> - reading files
> - reading data over a network
>
> This is best built-into a streaming toolbox, so that it happens
> automatically.
>
> Adriaan van Os

Don't forget to use packed records (see the Free Pascal Language
Reference Guide). I've used binary files in that way across linux and
windows machines (x86).

Gustavo