Is this a bug of module struct?

rong.xian

Before I was bitten by the difference below, I think these two ways are
the same.
However, they are not.
Is there any geek who can tell me if this is a bug?
(some weird '\x00\x00' was inserted between '0123456789abcd' and 6 )

>>struct.pack('3I14sI',1,19960101,14,'0123456789ab cd',6)

'\x01\x00\x00\x00%\x910\x01\x0e\x00\x00\x000123456 789abcd\x00\x00\x06\x00\x00\x00'

>>struct.pack('3I14s',1,19960101,14,'0123456789abc d')+struct.pack('I',6)

'\x01\x00\x00\x00%\x910\x01\x0e\x00\x00\x000123456 789abcd\x06\x00\x00\x00'

Aug 25 '06 #1

rong.xian

I got it, alignment issue...

>struct.pack('!3I14sI',1,19960101,14,'0123456789ab cd',6)

'\x01\x00\x00\x00%\x910\x01\x0e\x00\x00\x000123456 789abcd\x06\x00\x00\x00'

>struct.pack('!3I14s',1,19960101,14,'0123456789abc d')+struct.pack('!I',6)

'\x01\x00\x00\x00%\x910\x01\x0e\x00\x00\x000123456 789abcd\x06\x00\x00\x00'

rong.x...@gmail.com wrote:

Before I was bitten by the difference below, I think these two ways are
the same.
However, they are not.
Is there any geek who can tell me if this is a bug?
(some weird '\x00\x00' was inserted between '0123456789abcd' and 6 )

>struct.pack('3I14sI',1,19960101,14,'0123456789abc d',6)

'\x01\x00\x00\x00%\x910\x01\x0e\x00\x00\x000123456 789abcd\x00\x00\x06\x00\x00\x00'

>struct.pack('3I14s',1,19960101,14,'0123456789abcd ')+struct.pack('I',6)

'\x01\x00\x00\x00%\x910\x01\x0e\x00\x00\x000123456 789abcd\x06\x00\x00\x00'

Aug 25 '06 #2

Grant Edwards

On 2006-08-25, ro*******@gmail.com <ro*******@gmail.comwrote:

Before I was bitten by the difference below, I think these two
ways are the same. However, they are not.

As is explained here:

http://www.python.org/doc/current/li...le-struct.html

Is there any geek who can tell me if this is a bug?

Yes there is.

No it isn't a bug.

It's all explained in the manual: If you don't specify a byte
order, native byte order an alignment are assumed.

--
Grant Edwards grante Yow! NEWARK has been
at REZONED!! DES MOINES has
visi.com been REZONED!!

Aug 25 '06 #3