Scope of variables and link_message event

If I declare a global variable for sender_num in a link_message and substitute it for example

integer sndr;

default
{
state_entry()
{
llSay(0,"Hello Avatar";
}

touch_start(integer total_number)
{
llSay(0,"Touched";
}

link_message(sndr, integer num,string str, key id)
{
llSay(0,"Message received";
}
}

I get a compiler syntax error. What am I missing?

The linkmessage event is a then receives outside values. So you must use the format as listed in the function to receive the values from the event. You can then reassign it to a global variable.

Maybe this is what you want?

integer sndr;

default
{
   state_entry()
   {
      llSay(0,"Hello Avatar");
   }

   touch_start(integer total_number)
   {
      llSay(0,"Touched");
   }

   link_message(integer sender_num, integer num,string str, key id)
   {
      sndr = sender_num;
      llSay(0,"Message received");
   }
}

I thought that was it. I need to follow the default definition for link_message then reassign within the scope.