native callfunc_begin(const func, const plugin = "");
Plugin filename, if empty the calling plugin is targeted
The filename has to be the full exact name (e.g. stats.amxx)
Initiates a function call to this or another plugin by function name.
This only sets up the function call and covers the pre-requisites.
Push parameters using the callfunc_push_* set of functions. The call
will be executed only upon using callfunc_end()
1 on success
0 on runtime error
-1 if plugin was not found
-2 if function was not found
If called while another callfunc has not yet been finished,
an error is thrown.