diff --git a/src/platform/waiter_linux.h b/src/platform/waiter_linux.h
index 3bee40d..ac8b1c2 100644
--- a/src/platform/waiter_linux.h
+++ b/src/platform/waiter_linux.h
@@ -252,7 +252,7 @@ public:
         }
         // calc a new wait-id & construct event object
         event evt { ipc::detail::calc_unique_id() };
-        auto ids = static_cast<std::size_t*>(mem::alloc(sizeof(std::size_t[size])));
+        auto ids = static_cast<std::size_t*>(mem::alloc(sizeof(std::size_t) * size));
         for (std::size_t i = 0; i < size; ++i) {
             ids[i] = std::get<0>(all[i])->push_event(evt);
         }
@@ -260,7 +260,7 @@ public:
             for (std::size_t i = 0; i < size; ++i) {
                 std::get<0>(all[i])->pop_event(ids[i]);
             }
-            mem::free(ids, sizeof(std::size_t[size]));
+            mem::free(ids, sizeof(std::size_t) * size);
         });
         // wait for event signal
         return evt.wait();
diff --git a/src/platform/waiter_win.h b/src/platform/waiter_win.h
index 8e2378f..aa69d91 100644
--- a/src/platform/waiter_win.h
+++ b/src/platform/waiter_win.h
@@ -41,8 +41,8 @@ public:
         if (all == nullptr || size == 0) {
             return false;
         }
-        auto hs = static_cast<handle_t*>(mem::alloc(sizeof(handle_t[size])));
-        IPC_UNUSED_ auto guard = unique_ptr(hs, [size](void* p) { mem::free(p, sizeof(handle_t[size])); });
+        auto hs = static_cast<handle_t*>(mem::alloc(sizeof(handle_t) * size));
+        IPC_UNUSED_ auto guard = unique_ptr(hs, [size](void* p) { mem::free(p, sizeof(handle_t) * size); });
         std::size_t i = 0;
         for (; i < size; ++i) {
             auto& info = all[i];
@@ -52,7 +52,7 @@ public:
             hs[i] = std::get<1>(all[i]);
         }
         std::atomic_thread_fence(std::memory_order_release);
-        return ::WaitForMultipleObjects(hs, i, FALSE, INFINITE) != WAIT_FAILED;
+        return ::WaitForMultipleObjects(static_cast<DWORD>(i), hs, FALSE, INFINITE) != WAIT_FAILED;
     }
 
     bool wait(handle_t h) {
diff --git a/src/platform/waiter_wrapper.h b/src/platform/waiter_wrapper.h
index 6397282..050b897 100644
--- a/src/platform/waiter_wrapper.h
+++ b/src/platform/waiter_wrapper.h
@@ -67,8 +67,8 @@ public:
             return false;
         }
         using tp_t = decltype(std::declval<waiter_wrapper>().to_w_info());
-        auto hs = static_cast<tp_t*>(mem::alloc(sizeof(tp_t[size])));
-        IPC_UNUSED_ auto guard = unique_ptr(hs, [size](void* p) { mem::free(p, sizeof(tp_t[size])); });
+        auto hs = static_cast<tp_t*>(mem::alloc(sizeof(tp_t) * size));
+        IPC_UNUSED_ auto guard = unique_ptr(hs, [size](void* p) { mem::free(p, sizeof(tp_t) * size); });
         std::size_t i = 0;
         for (; i < size; ++i) {
             auto& w = all[i];