diff --git a/pkgs/ruby/ext/default/assert.c b/pkgs/ruby/ext/default/assert.c
index 3b89941..72e9294 100644
--- a/pkgs/ruby/ext/default/assert.c
+++ b/pkgs/ruby/ext/default/assert.c
@@ -8,8 +8,7 @@ static VALUE rb_KernAux_assert_cb_EQ(VALUE self, VALUE assert_cb);
 static
 VALUE rb_KernAux_assert_do(VALUE self, VALUE file, VALUE line, VALUE msg);
 
-static ID rb_intern_call;
-
+static ID rb_intern_call = Qnil;
 static VALUE rb_KernAux = Qnil;
 
 void init_assert()
diff --git a/pkgs/ruby/ext/default/cmdline.c b/pkgs/ruby/ext/default/cmdline.c
index df5bfa2..6c42c57 100644
--- a/pkgs/ruby/ext/default/cmdline.c
+++ b/pkgs/ruby/ext/default/cmdline.c
@@ -29,7 +29,8 @@ static const struct rb_data_type_struct info = {
     .flags = RUBY_TYPED_FREE_IMMEDIATELY,
 };
 
-static ID rb_intern_freeze, rb_intern_new;
+static ID rb_intern_freeze = Qnil;
+static ID rb_intern_new = Qnil;
 
 static VALUE rb_KernAux = Qnil;
 static VALUE rb_KernAux_Error = Qnil;
@@ -39,7 +40,7 @@ static VALUE rb_ANON_Data = Qnil;
 void init_cmdline()
 {
     rb_gc_register_mark_object(rb_intern_freeze = rb_intern("freeze"));
-    rb_gc_register_mark_object(rb_intern_new = rb_intern("new"));
+    rb_gc_register_mark_object(rb_intern_new    = rb_intern("new"));
 
     rb_gc_register_mark_object(rb_KernAux = rb_define_module("KernAux"));
     rb_gc_register_mark_object(rb_KernAux_Error =
@@ -48,6 +49,7 @@ void init_cmdline()
         rb_define_class_under(rb_KernAux, "CmdlineError", rb_KernAux_Error));
     rb_gc_register_mark_object(rb_ANON_Data =
         rb_funcall(rb_cClass, rb_intern_new, 1, rb_cObject));
+
     rb_define_alloc_func(rb_ANON_Data, rb_ANON_Data_ALLOC);
     rb_define_singleton_method(rb_KernAux, "cmdline", rb_KernAux_cmdline, 1);
 }
diff --git a/pkgs/ruby/ext/default/main.c b/pkgs/ruby/ext/default/main.c
index e29108b..6eff928 100644
--- a/pkgs/ruby/ext/default/main.c
+++ b/pkgs/ruby/ext/default/main.c
@@ -6,11 +6,6 @@
 #include <kernaux.h>
 #include <ruby.h>
 
-static ID rb_intern_LESS, rb_intern_call, rb_intern_freeze;
-
-static VALUE rb_KernAux = Qnil;
-static VALUE rb_KernAux_Error = Qnil;
-
 void init_assert();
 #ifdef HAVE_KERNAUX_SNPRINTF
 void init_printf();
@@ -26,6 +21,13 @@ static VALUE rb_KernAux_utoa10(VALUE self, VALUE number);
 static VALUE rb_KernAux_itoa10(VALUE self, VALUE number);
 #endif
 
+static ID rb_intern_LESS = Qnil;
+static ID rb_intern_call = Qnil;
+static ID rb_intern_freeze = Qnil;
+
+static VALUE rb_KernAux = Qnil;
+static VALUE rb_KernAux_Error = Qnil;
+
 void Init_default()
 {
     init_assert();
@@ -41,7 +43,6 @@ void Init_default()
     rb_gc_register_mark_object(rb_intern_freeze = rb_intern("freeze"));
 
     rb_gc_register_mark_object(rb_KernAux = rb_define_module("KernAux"));
-
     rb_gc_register_mark_object(rb_KernAux_Error =
         rb_define_class_under(rb_KernAux, "Error", rb_eRuntimeError));
 
diff --git a/pkgs/ruby/ext/default/printf.c b/pkgs/ruby/ext/default/printf.c
index 93b1f66..213914e 100644
--- a/pkgs/ruby/ext/default/printf.c
+++ b/pkgs/ruby/ext/default/printf.c
@@ -5,14 +5,12 @@
 
 static VALUE rb_KernAux_snprintf1(int argc, const VALUE *argv, VALUE self);
 
-static ID rb_intern_freeze;
-
+static ID rb_intern_freeze = Qnil;
 static VALUE rb_KernAux = Qnil;
 
 void init_printf()
 {
     rb_gc_register_mark_object(rb_intern_freeze = rb_intern("freeze"));
-
     rb_gc_register_mark_object(rb_KernAux = rb_define_module("KernAux"));
 
     rb_define_singleton_method(rb_KernAux, "snprintf1",