support thread_initialization.

pl/boot.yap

@@ -95,7 +95,8 @@ true :- true.
 	'$db_clean_queues'(0),
 	'$startup_reconsult',
 	'$startup_goals',
-	'$set_input'(user_input),'$set_output'(user).
+	'$set_input'(user_input),'$set_output'(user),
+	'$run_at_thread_start'.
 
 '$init_consult' :-
 	nb_setval('$lf_verbose',informational),
@@ -673,6 +674,12 @@ true :- true.
 	   write_term(user_error,G,Opts) ;
 	   format(user_error,'~w',[G])
         ).
+'$write_goal_output'(_M:G, First, [G|NG], next, NG) :-
+        ( First = first -> true ; format(user_error,',~n',[]) ),
+        ( recorded('$print_options','$toplevel'(Opts),_) ->
+	   write_term(user_error,G,Opts) ;
+	   format(user_error,'~w',[G])
+        ).
 
 '$name_vars_in_goals'(G, VL0, NG) :-
 	copy_term_nat(G+VL0, NG+NVL0),
@@ -1189,3 +1196,11 @@ throw(Ball) :-
 
 '$oncenotrace'(M:G) :-
 	'$execute_nonstop'(G, M), !.
+
+'$run_at_thread_start' :-
+	recorded('$thread_initialization',M:D,_),
+	'$notrace'(M:D),
+	fail.
+'$run_at_thread_start'.
+
+

pl/directives.yap

@@ -53,6 +53,7 @@
 '$directive'(reexport(_,_)).
 '$directive'(sequential).
 '$directive'(sequential(_)).
+'$directive'(thread_initialization(_)).
 '$directive'(thread_local(_)).
 '$directive'(uncutable(_)).
 '$directive'(use_module(_)).
@@ -74,6 +75,8 @@
 	'$discontiguous'(D,M).
 '$exec_directive'(initialization(D), _, M) :-
 	'$initialization'(M:D).
+'$exec_directive'(thread_initialization(D), _, M) :-
+	'$thread_initialization'(M:D).
 '$exec_directive'(expects_dialect(D), _, _) :-
 	'$expects_dialect'(D).
 '$exec_directive'(encoding(Enc), _, _) :-
@@ -1101,3 +1104,11 @@ user_defined_flag(Atom) :-
 	eraseall('$dialect'),
 	recorda('$dialect',yap,_).
 
+'$thread_initialization'(M:D) :-
+	eraseall('$thread_initialization'),
+	recorda('$thread_initialization',M:D,_),
+	fail.
+'$thread_initialization'(M:D) :-
+	'$initialization'(M:D).
+
+

pl/threads.yap

@@ -38,6 +38,7 @@
 	'$thread_self'(Id),
 	(Detached == true -> '$detach_thread'(Id) ; true),
 	'$current_module'(Module),
+	'$run_at_thread_start',
 	% always finish with a throw to make sure we clean stacks.
 	'$system_catch'((G -> throw('$thread_finished'(true)) ; throw('$thread_finished'(false))),Module,Exception,'$close_thread'(Exception,Detached)),
 	% force backtracking and handling exceptions