runtime: test that timeBeginPeriod succeeds

Change-Id: I5183f767dadb6d24a34d2460d02e97ddbaab129a
Reviewed-on: https://go-review.googlesource.com/12546
Run-TryBot: Minux Ma <minux@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

src/runtime/export_windows_test.go

@@ -6,4 +6,7 @@
 
 package runtime
 
-var TestingWER = &testingWER
+var (
+	TestingWER              = &testingWER
+	TimeBeginPeriodRetValue = &timeBeginPeriodRetValue
+)

src/runtime/os1_windows.go

@@ -139,6 +139,8 @@ const (
 // in sys_windows_386.s and sys_windows_amd64.s
 func externalthreadhandler()
 
+var timeBeginPeriodRetValue uint32
+
 func osinit() {
 	asmstdcallAddr = unsafe.Pointer(funcPC(asmstdcall))
 
@@ -154,7 +156,7 @@ func osinit() {
 
 	stdcall2(_SetConsoleCtrlHandler, funcPC(ctrlhandler), 1)
 
-	stdcall1(_timeBeginPeriod, 1)
+	timeBeginPeriodRetValue = uint32(stdcall1(_timeBeginPeriod, 1))
 
 	ncpu = getproccount()
 

src/runtime/syscall_windows_test.go

@@ -640,3 +640,10 @@ uintptr_t cfunc(callback f, uintptr_t n) {
 		t.Errorf("got %d want %d", got, want)
 	}
 }
+
+func TestTimeBeginPeriod(t *testing.T) {
+	const TIMERR_NOERROR = 0
+	if *runtime.TimeBeginPeriodRetValue != TIMERR_NOERROR {
+		t.Fatalf("timeBeginPeriod failed: it returned %d", *runtime.TimeBeginPeriodRetValue)
+	}
+}