2 files changed, 13 insertions, 0 deletions
diff --git a/spec/ruby/optional/capi/ext/thread_spec.c b/spec/ruby/optional/capi/ext/thread_spec.c
index 743828b523..53eae456b2 100644
--- a/spec/ruby/optional/capi/ext/thread_spec.c
+++ b/spec/ruby/optional/capi/ext/thread_spec.c
@@ -73,6 +73,14 @@ static void* blocking_gvl_func_for_udf_io(void *data) {
   }
 }
 
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wcast-function-type"
+static VALUE thread_spec_rb_thread_call_without_gvl_native_function(VALUE self) {
+  pid_t ret = (pid_t) (long) rb_thread_call_without_gvl((void *(*)(void *)) getpid, 0, RUBY_UBF_IO, 0);
+  return LONG2FIX(ret);
+}
+#pragma GCC diagnostic pop
+
 /* Returns true if the thread is interrupted. */
 static VALUE thread_spec_rb_thread_call_without_gvl_with_ubf_io(VALUE self) {
   int fds[2];
@@ -134,6 +142,7 @@ void Init_thread_spec(void) {
   VALUE cls = rb_define_class("CApiThreadSpecs", rb_cObject);
   rb_define_method(cls, "rb_thread_alone", thread_spec_rb_thread_alone, 0);
   rb_define_method(cls, "rb_thread_call_without_gvl", thread_spec_rb_thread_call_without_gvl, 0);
+  rb_define_method(cls, "rb_thread_call_without_gvl_native_function", thread_spec_rb_thread_call_without_gvl_native_function, 0);
   rb_define_method(cls, "rb_thread_call_without_gvl_with_ubf_io", thread_spec_rb_thread_call_without_gvl_with_ubf_io, 0);
   rb_define_method(cls, "rb_thread_current", thread_spec_rb_thread_current, 0);
   rb_define_method(cls, "rb_thread_local_aref", thread_spec_rb_thread_local_aref, 2);
diff --git a/spec/ruby/optional/capi/thread_spec.rb b/spec/ruby/optional/capi/thread_spec.rb
index df454d1ea8..35b58996b8 100644
--- a/spec/ruby/optional/capi/thread_spec.rb
+++ b/spec/ruby/optional/capi/thread_spec.rb
@@ -121,6 +121,10 @@ describe "C-API Thread function" do
       thr.value.should be_true
     end
 
+    it "runs a native function with the global lock unlocked" do
+      @t.rb_thread_call_without_gvl_native_function.should == Process.pid
+    end
+
     guard -> { platform_is :mingw and ruby_version_is ""..."2.7" } do
       it "runs a C function with the global lock unlocked and unlocks IO with the generic RUBY_UBF_IO" do
         thr = Thread.new do