[syslog-ng]Which signal does reload sends ?

[Ali EL MOUSSAWI]

Hi all
Can you please tell me what happens when syslog-ng reloads (i.e. 
receives HUP signal) ?
I need to know what signal does it send to the destination programs, and 
is it a good practice to catch this signal. In fact I don't want my 
destination program to die at reload, or at least I want to serialize 
his data structures before it dies, in order to retrieve it when it goes 
back.

On the other hand, if a message arrives from an UDP source while 
syslog-ng is reloading, will it be lost ? Why the keep alive option is 
only for tcp source ?
Thanks a lot for any help

Ali