The underlaying CANlib library is initialized when the module
is imported. This will initialize the CANlib library and enumerate all
currently available CAN channels.
Library Deinitialization and Cleanup¶
Strictly speaking it is not necessary to clean up anything before terminating the application. If the application quits unexpectedly, the device driver will ensure the CAN controller is deactivated and the driver will also ensure the firmware (if any) is left in a consistent state.
To reinitialize the library in an orderly fashion you may want to call
canlib.Channel.writeSync with a short timeout for each open handle
before closing them with
canlib.Channel.close, to ensure the transmit
queues are empty. You can then start afresh by calling
Manually Enumerating CAN channels¶
canlib.enumerate_hardware scans all currently connected devices
and creates a completely new set of CANlib channel numbers, while still keeping
all currently opened channel handles valid and usable. This can be viewed upon
as a replacement for calling
canlib.reinitializeLibrary which do invalidate
all open channel handles.
One thing to keep in mind when using this functionality is to never track
devices based on their CANlib channel number, since this number may change
enumerate_hardware is called. To retrieve information about a
specific channel use
Channel.channel_data to get a safe
ChannelData, instead of relying on an old
ChannelData object created from a channel number.
On Linux, no re-enumeration is needed since enumeration takes place when a device is plugged in or unplugged.