I'm using the C driver in a program. I have set my own logging handler function (as described in http://mongoc.org/libmongoc/current/logging.html) to avoid printing anything in standard output (my function writes to a log file instead that standard output).

However, I'm still getting this kind of warning in my programs output:

2021/02/04 22:33:32.0740: [ 6745]: WARNING: mongoc: Falling back to malloc for counters.

Should I understand that kind of "Failling back to malloc for counters" warning are not managed by the logging handler and always go to standard output? Or should they and I'm doing something wrong in my program?

(I have seen issue https://jira.mongodb.org/browse/CDRIVER-1504, which provides a solution to disable "Failling back to malloc for counters" warning. However, note that in my case I want these warning... but managed properly by my logging handler instead that printed in standard output)