[OLSR-users] hello message generation

[Bing]

I am doing little modification to the core functions. To trace my
modifications, I set printf inside modules such as build_msg.c. But I
just can't see my message printed when running OLSR. I thought the HELLO
message would be automatically generated as long as OLSR is on, and
traversing the build_message functions is necessary. If not, what
triggers the generation of all these messages? 
Maybe this question is so silly, but I would appreciate it if is is
answered.

Bing