Hi Volker,

> I couldn't understand too, but with your sizeof(char) question you made me 
> curious.
> 
> On x86_64, int has a size of 4 and size_t takes 8 (while on x86 both have a 
> size of 4).
> By passing &len to g_io_channel_read (which takes a size_t *buffer_read as 
> argument), we blank out the first four bytes of buf - which sits directly 
> after len in memory ('oh wonderful world...').
> 
> > This can be a problem that the call of the PIN helper program fails.
> This problem is also solved with the change from int len to size_t len.
> 
> So, please trash my first patch and take this instead.

and here is the patch I am going to apply. Please test it.

Regards

Marcel