os.system error returns

[Grawburg]

I have a piece of code written for a Raspberry Pi with no explanation for two of the lines -- and I can't find an explanation I understand.

Here are the lines:
if os.system('modprobe --first-time -q w1_gpio') ==0

if os.system('modprobe -q w1_gpio') == 256:



I know what the 'modprobe...' is, it's the 0 and the 256 I don't get. Where do these numbers come from?
I recognize they're some kind of error returns, but don't know what they mean.


Thanks,
Brian Grawburg