# Initialization

## Library Initialization

The underlaying CANlib library is initialized when the module `canlib.canlib` 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 `canlib.reinitializeLibrary`.

Note

When calling `canlib.reinitializeLibrary`, all previously opened CAN handles (`canlib.Channel`) will be closed and invalidated.

## Manually Enumerating CAN channels

The function `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 anytime `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.

Note

On Linux, no re-enumeration is needed since enumeration takes place when a device is plugged in or unplugged.