diff --git a/include/libipc/event.h b/include/libipc/event.h
index d10e622..ee56ac7 100644
--- a/include/libipc/event.h
+++ b/include/libipc/event.h
@@ -36,7 +36,7 @@ LIBIMP_EXPORT ::LIBIMP::result<void> evt_set(evt_t) noexcept;
 LIBIMP_EXPORT ::LIBIMP::result<bool> evt_wait(evt_t, std::int64_t ms) noexcept;
 
 /// \brief Waits until one or all of the specified objects are in the signaled state or the time-out interval elapses.
-LIBIMP_EXPORT ::LIBIMP::result<bool> evt_wait(::LIBIMP::span<evt_t>, std::int64_t ms) noexcept;
+LIBIMP_EXPORT ::LIBIMP::result<bool> evt_wait(::LIBIMP::span<evt_t const>, std::int64_t ms) noexcept;
 
 /**
  * \brief The event object.
diff --git a/src/libipc/event.cpp b/src/libipc/event.cpp
index 3f14aef..81fb9cb 100644
--- a/src/libipc/event.cpp
+++ b/src/libipc/event.cpp
@@ -1,8 +1,6 @@
 
 #include "libimp/log.h"
 
-#include "libimp/detect_plat.h"
-
 #include "libimp/detect_plat.h"
 #if defined(LIBIMP_OS_WIN)
 # include "libipc/platform/win/event_impl.h"
diff --git a/src/libipc/platform/win/event_impl.h b/src/libipc/platform/win/event_impl.h
index ca892f6..90e1f64 100644
--- a/src/libipc/platform/win/event_impl.h
+++ b/src/libipc/platform/win/event_impl.h
@@ -42,7 +42,10 @@ bool is_valid(evt_t evt) noexcept {
 result<evt_t> evt_open(std::string name) noexcept {
   LIBIMP_LOG_();
   auto t_name = detail::to_tstring(name);
-  auto h = ::CreateEvent(detail::get_sa(), FALSE, FALSE, t_name.c_str());
+  auto h = ::CreateEvent(detail::get_sa(), 
+                        /*bManualReset*/ FALSE, 
+                        /*bInitialState*/FALSE, 
+                        /*lpName*/       t_name.c_str());
   if (h == NULL) {
     auto err = sys::error();
     log.error("failed: CreateEvent(FALSE, FALSE, ", name, "). error = ", err);
@@ -119,7 +122,7 @@ result<bool> evt_wait(evt_t evt, std::int64_t ms) noexcept {
  * \brief Waits until one or all of the specified objects are in the signaled state or the time-out interval elapses.
  * \see https://learn.microsoft.com/en-us/windows/win32/api/synchapi/nf-synchapi-waitformultipleobjects
  */
-result<bool> evt_wait(::LIBIMP::span<evt_t> evts, std::int64_t ms) noexcept {
+result<bool> evt_wait(::LIBIMP::span<evt_t const> evts, std::int64_t ms) noexcept {
   LIBIMP_LOG_();
   if (evts.empty()) {
     log.error("evts handle is empty.");
diff --git a/test/ipc/test_ipc_event.cpp b/test/ipc/test_ipc_event.cpp
index fcd9c51..a0332b1 100644
--- a/test/ipc/test_ipc_event.cpp
+++ b/test/ipc/test_ipc_event.cpp
@@ -1,4 +1,6 @@
 
+#include <thread>
+
 #include "gtest/gtest.h"
 
 #include <libipc/event.h>
@@ -10,10 +12,88 @@ TEST(event, open_close) {
   ASSERT_TRUE(ipc::evt_close(*evt));
 }
 
+TEST(event, wait_timeout) {
+  auto evt = ipc::evt_open("test");
+  ASSERT_TRUE(evt);
+  ASSERT_FALSE(*ipc::evt_wait(*evt, 0));
+  ASSERT_TRUE(ipc::evt_close(*evt));
+}
+
 TEST(event, set_wait) {
   auto evt = ipc::evt_open("test");
   ASSERT_TRUE(evt);
   ASSERT_TRUE(ipc::evt_set(*evt));
-  ASSERT_TRUE(ipc::evt_wait(*evt, 0));
+  ASSERT_TRUE(*ipc::evt_wait(*evt, 0));
   ASSERT_TRUE(ipc::evt_close(*evt));
 }
+
+TEST(event, unicast) {
+  auto evt = ipc::evt_open("test");
+  ASSERT_TRUE(evt);
+  int success = 0;
+  auto wait = [evt, &success] {
+    if (*ipc::evt_wait(*evt, 200)) ++success;
+  };
+  auto th1 = std::thread(wait);
+  auto th2 = std::thread(wait);
+  auto th3 = std::thread(wait);
+  std::this_thread::sleep_for(std::chrono::milliseconds(100));
+  ASSERT_TRUE(ipc::evt_set(*evt));
+  th1.join();
+  th2.join();
+  th3.join();
+  ASSERT_TRUE(ipc::evt_close(*evt));
+  ASSERT_EQ(success, 1);
+}
+
+TEST(event, wait_multi_timeout) {
+  auto evt1 = ipc::evt_open("test1");
+  ASSERT_TRUE(evt1);
+  auto evt2 = ipc::evt_open("test2");
+  ASSERT_TRUE(evt2);
+  auto evt3 = ipc::evt_open("test3");
+  ASSERT_TRUE(evt3);
+  ASSERT_FALSE(*ipc::evt_wait(imp::make_span({*evt1, *evt2, *evt3}), 0));
+  ASSERT_TRUE(ipc::evt_close(*evt1));
+  ASSERT_TRUE(ipc::evt_close(*evt2));
+  ASSERT_TRUE(ipc::evt_close(*evt3));
+}
+
+TEST(event, set_wait_multi) {
+  auto evt1 = ipc::evt_open("test1");
+  ASSERT_TRUE(evt1);
+  auto evt2 = ipc::evt_open("test2");
+  ASSERT_TRUE(evt2);
+  auto evt3 = ipc::evt_open("test3");
+  ASSERT_TRUE(evt3);
+  ASSERT_TRUE(ipc::evt_set(*evt2));
+  ASSERT_TRUE(*ipc::evt_wait(imp::make_span({*evt1, *evt2, *evt3}), 0));
+  ASSERT_TRUE(ipc::evt_close(*evt1));
+  ASSERT_TRUE(ipc::evt_close(*evt2));
+  ASSERT_TRUE(ipc::evt_close(*evt3));
+}
+
+TEST(event, unicast_multi) {
+  auto evt1 = ipc::evt_open("test1");
+  ASSERT_TRUE(evt1);
+  auto evt2 = ipc::evt_open("test2");
+  ASSERT_TRUE(evt2);
+  auto evt3 = ipc::evt_open("test3");
+  ASSERT_TRUE(evt3);
+  int success = 0;
+  auto wait = [evt1, evt2, evt3, &success] {
+    if (*ipc::evt_wait(imp::make_span({*evt1, *evt2, *evt3}), 200)) ++success;
+  };
+  auto th1 = std::thread(wait);
+  auto th2 = std::thread(wait);
+  auto th3 = std::thread(wait);
+  std::this_thread::sleep_for(std::chrono::milliseconds(100));
+  ASSERT_TRUE(ipc::evt_set(*evt3));
+  th1.join();
+  th2.join();
+  th3.join();
+  ASSERT_TRUE(ipc::evt_close(*evt1));
+  ASSERT_TRUE(ipc::evt_close(*evt2));
+  ASSERT_TRUE(ipc::evt_close(*evt3));
+  ASSERT_EQ(success, 1);
+}