Return user data previously attached to device using the specified key. If no user data has been attached with the given key this function returns NULL. Since 1.10
the address of the cairo_user_data_key_t the user data was attached to
the user data previously attached or NULL.
See Implementation
Return user data previously attached to device using the specified key. If no user data has been attached with the given key this function returns NULL. Since 1.10