library mode: how to catch error/warning messages ?

[TraumaEnSOes]

I'm using fluent as a library, so I can make configuration changes on the fly.

I'm interested in catching possible errors: for example, the 'http' output tries to connect to a down server. That's my main interest, intercepting general and module specific 'http' errors.

I can't find a way to receive notifications about it; the only thing I have found is the possibility to intercept the log outputs (to stderr) and interpret them.

Is there any way to receive notifications about errors in the program that uses the library ?