[sr-dev] Re: [kamailio/kamailio] core: add support for custom log function (PR #3902)

Does it affect in any way the modules log_custom or log_systemd?

It does not. Mentioned modules rely on the `_km_log_func` (set via `km_log_func_set`) while this patch uses `_km_custom_log_func` (set via `km_custom_log_func_set`) and makes no changes to the `_km_log_func`. The only downside is that if the feature from this patch is enabled using the `CUSTOM_LOG_FMT`, then default log macros will bypass `_km_log_func` and will use `_km_custom_log_func` instead. In short - mentioned modules are currently not compatible with this patch.