kc3-lang/kc3

diff --git a/libc3/facts.c b/libc3/facts.c
index e73069c..7205986 100644
--- a/libc3/facts.c
+++ b/libc3/facts.c
@@ -73,6 +73,7 @@ void facts_clean (s_facts *facts)
   skiplist_delete__fact(facts->index_spo);
   set_clean__fact(&facts->facts);
   set_clean__tag(&facts->tags);
+  pthread_rwlock_destroy(&facts->rwlock);
 }
 
 void facts_close (s_facts *facts)
@@ -201,6 +202,8 @@ s_facts * facts_init (s_facts *facts)
   assert(facts->index_osp);
   facts->index_osp->compare = compare_fact_osp;
   facts->log = NULL;
+  if (pthread_rwlock_init(&facts->rwlock, NULL))
+    errx(1, "pthread_rwlock_init");
   return facts;
 }
 
diff --git a/libc3/types.h b/libc3/types.h
index c515ed7..216c2ff 100644
--- a/libc3/types.h
+++ b/libc3/types.h
@@ -18,6 +18,7 @@
 #include <stdio.h>
 #include <sys/types.h>
 #include <ffi.h>
+#include <pthread.h>
 #include "config.h"
 #include "sha1.h"
 #include "../libtommath/tommath.h"
@@ -409,6 +410,7 @@ struct facts {
   s_skiplist__fact *index_pos;
   s_skiplist__fact *index_osp;
   s_log            *log;
+  pthread_rwlock_t  rwlock;
 };
 
 struct facts_cursor {