1 files changed, 1 insertions, 1 deletions

diff --git a/src/tools.c b/src/tools.c
index 9a1c19d..f1b0372 100644
--- a/src/tools.c
+++ b/src/tools.c
@@ -224,7 +224,7 @@ static void open1lib( struct s_Universe* U, lua_State* L, char const* name_, siz
                         if( libfunc != NULL)
                         {
                                 bool_t const isLanesCore = (libfunc == require_lanes_core) ? TRUE : FALSE; // don't want to create a global for "lanes.core"
-                                DEBUGSPEW_CODE( fprintf( stderr, INDENT_BEGIN "opening %.*s library\n" INDENT_END, len_, name_));
+                                DEBUGSPEW_CODE( fprintf( stderr, INDENT_BEGIN "opening %.*s library\n" INDENT_END, (int) len_, name_));
                                 STACK_CHECK( L);
                                 if( isLanesCore == TRUE)
                                 {