How to write a warning to my log file?

[MarkyMarc]

Hi All,

A small newbie Q.

I have made a nice log function in me program. The program writes some
data to me mysql database.
When I write to the database I get som warnings back.

Have do I write these to me log file?
I know I have to use the the warnings api. But I can not figure out
how to use it.
Is there anyone take might give me a small example.

THX all :-)