[libhid-discuss] match_serial_number and python

[Li-Wei Chen]

Hi,

I'm successfully using libhid to talk to a single USB device, and I'd 
ultimately like to be able to address multiple devices of the same model 
from the same vendor.  Happily, although each device has the same 
vendor_id and product_id, the serial string associated with each device 
is unique.  In C, I'm able to follow the pattern in test_libhid.c to 
modify match_serial_number appropriately and pass that in 
HIDInterfaceMatcher to hid_force_open and select based on the serials.

I'm wondering if there's a way to accomplish the same thing using the 
included python modules if I prefer to code in python as opposed to C. 
I do see that there is a HIDInterfaceMatcher object, but test_libhid.py 
only sets vendor_id and product_id properties.  Digging into hid.h 
further suggests that the matcher functionality available in C is not 
available in python:

typedef struct HIDInterfaceMatcher_t {
   unsigned short vendor_id;
   unsigned short product_id;
#ifndef SWIG
   matcher_fn_t matcher_fn;      //!< Only supported in C library (not 
via SWIG)
   void* custom_data;               //!< Only used by matcher_fn
   unsigned int custom_data_length; //!< Only used by matcher_fn
#endif
} HIDInterfaceMatcher;

Can I correctly conclude from this that if I want to be able to match 
USB devices based on their serials, I'll need to write my code in C?

Thanks,

-- Li-Wei