[fpc-pascal] Re: Code works on Linux x64 but not on Linux x86

[Reinier Olislagers]

On 7-2-2012 19:48, Sven Barth wrote:
> On 07.02.2012 17:12, Reinier Olislagers wrote:
>>
>> Code bombs at decoder.Read(a, readsize). readsize=0 according to
>> debugger.
>> readsize=cardinal; according to help "an unsigned 32-bit integer".
>> However,
>> http://wiki.lazarus.freepascal.org/Multiplatform_Programming_Guide#32.2F64_bit
>>
>> seems to imply Cardinal can vary between 32 bit and 64 bit.
>>
>> Is that the culprit or am I doing anyth else wrong?
Thanks, Sven!

> Does your stream contain at least 4096 bytes? According to the
> documentation here
> http://www.freepascal.org/docs-html/rtl/objects/tstream.read.html the
> Read procedure does not perform any check.
Yes, that should be the case, compressed size is 909094 bytes. The file
uncompresses nicely with the bunzip2 executable.

> Important note in case you're not aware of it: Tbzip2_decode_stream is
> NOT a descendant of Classes.TStream, but of Objects.TStream, thus you
> should look at the documentation of unit Objects (you can reach it from
> the above mentioned link).
Ok, thanks.

> Also "Cardinal" is always 32-Bit wide. The only types that change
> depending on bitness are "Pointer", "PtrUInt" and "PtrInt".
Thanks.
Let me verify if I understand correctly. The wiki article
http://wiki.lazarus.freepascal.org/Multiplatform_Programming_Guide#32.2F64_bit
says:
FPC defines two types for this: PtrInt and PtrUInt. PtrInt is a 32bit
signed integer on 32 bit platforms and a 64bit signed integer on 64bit
platforms. The same for PtrUInt, but unsigned integer instead.

Use for code that should work with Delphi and FPC:

{$IFNDEF FPC}
type
  PtrInt = integer;
  PtrUInt = cardinal;
{$ENDIF}


So in Delphi, presumably cardinal varies between 32 and 64 bit, while in
FPC it is always 32 bit. Or am I interpreting this incorrectly?

I'll try and upgrade the FPC to SVN first - now at
Free Pascal Compiler version 2.6.0-1 [2012/01/13] for i386
maybe it helps... (Probably not).

I can also try the same code on Windows x86 to see what happens there...
Any additional tips welcome...


Thanks,
Reinier