diff --git a/ext/hbsdctl.rb/feature.c b/ext/hbsdctl.rb/feature.c
index 35a1469..1295da9 100644
--- a/ext/hbsdctl.rb/feature.c
+++ b/ext/hbsdctl.rb/feature.c
@@ -20,6 +20,7 @@ feature_set(VALUE self, VALUE rb_path, VALUE rb_state)
 static VALUE
 __set(VALUE rb_path, VALUE rb_feature, VALUE rb_state)
 {
+  errno = 0;
   int result = hbsdcontrol_set_feature_state(
     RSTRING_PTR(rb_path),
     RSTRING_PTR(rb_feature),
diff --git a/ext/hbsdctl.rb/ffi.c b/ext/hbsdctl.rb/ffi.c
index c3326c9..8645af3 100644
--- a/ext/hbsdctl.rb/ffi.c
+++ b/ext/hbsdctl.rb/ffi.c
@@ -73,6 +73,7 @@ ffi_status(VALUE self, VALUE rb_feature, VALUE rb_path)
   char enable_data[2], disable_data[2];
   int ns;
 
+  errno = 0;
   options = __options_init(rb_feature, rb_path);
   if (extattr_string_to_namespace("system", &ns) == -1) {
     rb_syserr_fail(errno, "extattr_string_to_namespace");