diff --git a/include/def.h b/include/def.h
index 6764d31..945c0ef 100644
--- a/include/def.h
+++ b/include/def.h
@@ -29,7 +29,8 @@ using uint_t = typename uint<N>::type;
 enum : std::size_t {
     invalid_value = (std::numeric_limits<std::size_t>::max)(),
     data_length   = 64,
-    name_length   = 64
+    name_length   = 64,
+    send_wait_for = 100 // ms
 };
 
 enum class relat { // multiplicity of the relationship
diff --git a/include/ipc.h b/include/ipc.h
index 80ca8a2..b851d70 100644
--- a/include/ipc.h
+++ b/include/ipc.h
@@ -19,10 +19,10 @@ struct IPC_EXPORT chan_impl {
     static void     disconnect(handle_t h);
 
     static std::size_t recv_count(handle_t h);
-    static bool wait_for_recv(handle_t h, std::size_t r_count);
+    static bool wait_for_recv(handle_t h, std::size_t r_count, std::size_t tm);
 
     static bool   send(handle_t h, void const * data, std::size_t size);
-    static buff_t recv(handle_t h);
+    static buff_t recv(handle_t h, std::size_t tm);
 };
 
 template <typename Flag>
@@ -92,12 +92,12 @@ public:
         return detail_t::recv_count(h_);
     }
 
-    bool wait_for_recv(std::size_t r_count) const {
-        return detail_t::wait_for_recv(h_, r_count);
+    bool wait_for_recv(std::size_t r_count, std::size_t tm = invalid_value) const {
+        return detail_t::wait_for_recv(h_, r_count, tm);
     }
 
-    static bool wait_for_recv(char const * name, std::size_t r_count) {
-        return chan_wrapper(name).wait_for_recv(r_count);
+    static bool wait_for_recv(char const * name, std::size_t r_count, std::size_t tm = invalid_value) {
+        return chan_wrapper(name).wait_for_recv(r_count, tm);
     }
 
     bool send(void const * data, std::size_t size) {
@@ -112,8 +112,8 @@ public:
         return this->send(str.c_str(), str.size() + 1);
     }
 
-    buff_t recv() {
-        return detail_t::recv(h_);
+    buff_t recv(std::size_t tm = invalid_value) {
+        return detail_t::recv(h_, tm);
     }
 };
 
diff --git a/include/waiter.h b/include/waiter.h
index cc3b10d..91bea3c 100644
--- a/include/waiter.h
+++ b/include/waiter.h
@@ -1,6 +1,7 @@
 #pragma once
 
 #include "export.h"
+#include "def.h"
 
 namespace ipc {
 
@@ -22,7 +23,7 @@ public:
     bool open (char const * name);
     void close();
 
-    bool lock();
+    bool lock  ();
     bool unlock();
 
 private:
@@ -49,7 +50,7 @@ public:
     bool open (char const * name, long count = 0);
     void close();
 
-    bool wait();
+    bool wait(std::size_t tm = invalid_value);
     bool post(long count = 1);
 
 private:
@@ -74,7 +75,7 @@ public:
     bool open (char const * name);
     void close();
 
-    bool wait(mutex&);
+    bool wait(mutex&, std::size_t tm = invalid_value);
     bool notify();
     bool broadcast();
 
diff --git a/src/ipc.cpp b/src/ipc.cpp
index 9bd6b67..2d8cf2b 100644
--- a/src/ipc.cpp
+++ b/src/ipc.cpp
@@ -76,16 +76,19 @@ struct cache_t {
 };
 
 template <typename W, typename F>
-void wait_for(W& waiter, F&& pred) {
+bool wait_for(W& waiter, F&& pred, std::size_t tm) {
     for (unsigned k = 0; pred();) {
-        bool ret = true;
-        ipc::sleep(k, [&ret, &waiter, &pred] {
-            return waiter.wait_if([&ret, &pred] {
-                return ret = pred();
-            });
+        bool loop = true, ret = true;
+        ipc::sleep(k, [&loop, &ret, &waiter, &pred, tm] {
+            ret = waiter.wait_if([&loop, &ret, &pred] {
+                return loop = pred();
+            }, tm);
+            return true;
         });
-        if (!ret) break;
+        if (!ret ) return false; // timeout or fail
+        if (!loop) break;
     }
+    return true;
 }
 
 template <typename Policy>
@@ -156,15 +159,14 @@ static std::size_t recv_count(ipc::handle_t h) {
     return que->conn_count();
 }
 
-static bool wait_for_recv(ipc::handle_t h, std::size_t r_count) {
+static bool wait_for_recv(ipc::handle_t h, std::size_t r_count, std::size_t tm) {
     auto que = queue_of(h);
     if (que == nullptr) {
         return false;
     }
-    wait_for(info_of(h)->cc_waiter_, [que, r_count] {
+    return wait_for(info_of(h)->cc_waiter_, [que, r_count] {
         return que->conn_count() < r_count;
-    });
-    return true;
+    }, tm);
 }
 
 static bool send(ipc::handle_t h, void const * data, std::size_t size) {
@@ -201,7 +203,7 @@ static bool send(ipc::handle_t h, void const * data, std::size_t size) {
     return true;
 }
 
-static buff_t recv(ipc::handle_t h) {
+static buff_t recv(ipc::handle_t h, std::size_t tm) {
     auto que = queue_of(h);
     if (que == nullptr) return {};
     if (que->connect()) { // wouldn't connect twice
@@ -211,9 +213,10 @@ static buff_t recv(ipc::handle_t h) {
     while (1) {
         // pop a new message
         typename queue_t::value_t msg;
-        wait_for(info_of(h)->rd_waiter_, [que, &msg] {
-            return !que->pop(msg);
-        });
+        if (!wait_for(info_of(h)->rd_waiter_,
+                      [que, &msg] { return !que->pop(msg); }, tm)) {
+            return {};
+        }
         if (msg.head_.que_ == nullptr) return {};
         if (msg.head_.que_ == que) continue; // pop next
         // msg.head_.remain_ may minus & abs(msg.head_.remain_) < data_length
@@ -279,8 +282,8 @@ std::size_t chan_impl<Flag>::recv_count(ipc::handle_t h) {
 }
 
 template <typename Flag>
-bool chan_impl<Flag>::wait_for_recv(ipc::handle_t h, std::size_t r_count) {
-    return detail_impl<policy_t<Flag>>::wait_for_recv(h, r_count);
+bool chan_impl<Flag>::wait_for_recv(ipc::handle_t h, std::size_t r_count, std::size_t tm) {
+    return detail_impl<policy_t<Flag>>::wait_for_recv(h, r_count, tm);
 }
 
 template <typename Flag>
@@ -289,8 +292,8 @@ bool chan_impl<Flag>::send(ipc::handle_t h, void const * data, std::size_t size)
 }
 
 template <typename Flag>
-buff_t chan_impl<Flag>::recv(ipc::handle_t h) {
-    return detail_impl<policy_t<Flag>>::recv(h);
+buff_t chan_impl<Flag>::recv(ipc::handle_t h, std::size_t tm) {
+    return detail_impl<policy_t<Flag>>::recv(h, tm);
 }
 
 template struct chan_impl<ipc::wr<relat::single, relat::single, trans::unicast  >>;
diff --git a/src/platform/waiter_linux.h b/src/platform/waiter_linux.h
index 9503596..516d9fa 100644
--- a/src/platform/waiter_linux.h
+++ b/src/platform/waiter_linux.h
@@ -5,6 +5,7 @@
 #include <sys/stat.h>
 #include <semaphore.h>
 #include <errno.h>
+#include <time.h>
 
 #include <atomic>
 #include <tuple>
@@ -17,6 +18,12 @@
 namespace ipc {
 namespace detail {
 
+inline static void calc_wait_time(timespec& ts, std::size_t tm) {
+    ::clock_gettime(CLOCK_REALTIME, &ts);
+    ts.tv_sec  += (tm / 1000);           // seconds
+    ts.tv_nsec += (tm % 1000) * 1000000; // nanoseconds
+}
+
 #pragma push_macro("IPC_PTHREAD_FUNC_")
 #undef  IPC_PTHREAD_FUNC_
 #define IPC_PTHREAD_FUNC_(CALL, ...)                \
@@ -96,8 +103,15 @@ public:
         IPC_PTHREAD_FUNC_(pthread_cond_destroy, &cond_);
     }
 
-    bool wait(mutex& mtx) {
-        IPC_PTHREAD_FUNC_(pthread_cond_wait, &cond_, &mtx.native());
+    bool wait(mutex& mtx, std::size_t tm = invalid_value) {
+        if (tm == invalid_value) {
+            IPC_PTHREAD_FUNC_(pthread_cond_wait, &cond_, &mtx.native());
+        }
+        else {
+            timespec ts;
+            calc_wait_time(ts, tm);
+            IPC_PTHREAD_FUNC_(pthread_cond_timedwait, &cond_, &mtx.native(), &ts);
+        }
     }
 
     bool notify() {
@@ -130,8 +144,8 @@ public:
 
 #pragma push_macro("IPC_SEMAPHORE_FUNC_")
 #undef  IPC_SEMAPHORE_FUNC_
-#define IPC_SEMAPHORE_FUNC_(CALL, PAR)              \
-    if (::CALL(PAR) != 0) {                         \
+#define IPC_SEMAPHORE_FUNC_(CALL, ...)              \
+    if (::CALL(__VA_ARGS__) != 0) {                 \
         ipc::error("fail " #CALL "[%d]\n", errno);  \
         return false;                               \
     }                                               \
@@ -151,9 +165,16 @@ public:
         IPC_SEMAPHORE_FUNC_(sem_post, h);
     }
 
-    static bool wait(handle_t h) {
+    static bool wait(handle_t h, std::size_t tm = invalid_value) {
         if (h == invalid()) return false;
-        IPC_SEMAPHORE_FUNC_(sem_wait, h);
+        if (tm == invalid_value) {
+            IPC_SEMAPHORE_FUNC_(sem_wait, h);
+        }
+        else {
+            timespec ts;
+            calc_wait_time(ts, tm);
+            IPC_SEMAPHORE_FUNC_(sem_timedwait, h, &ts);
+        }
     }
 
 #pragma pop_macro("IPC_SEMAPHORE_FUNC_")
@@ -204,14 +225,14 @@ public:
     }
 
     template <typename F>
-    bool wait_if(handle_t const & h, F&& pred) {
+    bool wait_if(handle_t const & h, F&& pred, std::size_t tm = invalid_value) {
         waiting_.fetch_add(1, std::memory_order_release);
         {
             IPC_UNUSED_ auto guard = ipc::detail::unique_lock(lock_);
             if (!std::forward<F>(pred)()) return true;
             ++ counter_;
         }
-        bool ret = sem_helper::wait(std::get<1>(h));
+        bool ret = sem_helper::wait(std::get<1>(h), tm);
         waiting_.fetch_sub(1, std::memory_order_release);
         ret = sem_helper::post(std::get<2>(h)) && ret;
         return ret;
@@ -283,9 +304,9 @@ public:
     }
 
     template <typename F>
-    bool wait_if(handle_t h, F&& pred) {
+    bool wait_if(handle_t h, F&& pred, std::size_t tm = invalid_value) {
         if (h == invalid()) return false;
-        return helper_.wait_if(h, std::forward<F>(pred));
+        return helper_.wait_if(h, std::forward<F>(pred), tm);
     }
 
     void notify(handle_t h) {
diff --git a/src/platform/waiter_win.h b/src/platform/waiter_win.h
index fbe08de..bcee368 100644
--- a/src/platform/waiter_win.h
+++ b/src/platform/waiter_win.h
@@ -33,11 +33,15 @@ public:
         ::CloseHandle(h_);
     }
 
-    bool wait() {
-        DWORD ret;
-        if ((ret = ::WaitForSingleObject(h_, INFINITE)) == WAIT_OBJECT_0) {
+    bool wait(std::size_t tm = invalid_value) {
+        DWORD ret, ms = (tm == invalid_value) ? INFINITE : static_cast<DWORD>(tm);
+        if ((ret = ::WaitForSingleObject(h_, ms)) == WAIT_OBJECT_0) {
             return true;
         }
+        if (ret == WAIT_TIMEOUT) {
+            ipc::log("WaitForSingleObject is timeout.\n");
+            return false;
+        }
         ipc::error("fail WaitForSingleObject[%lu]: 0x%08X\n", ::GetLastError(), ret);
         return false;
     }
@@ -98,7 +102,7 @@ public:
     }
 
     template <typename Mutex, typename F>
-    bool wait_if(Mutex& mtx, F&& pred) {
+    bool wait_if(Mutex& mtx, F&& pred, std::size_t tm = invalid_value) {
         waiting_->fetch_add(1, std::memory_order_release);
         {
             IPC_UNUSED_ auto guard = ipc::detail::unique_lock(lock_);
@@ -106,7 +110,7 @@ public:
             ++ *counter_;
         }
         mtx.unlock();
-        bool ret = sema_.wait();
+        bool ret = sema_.wait(tm);
         waiting_->fetch_sub(1, std::memory_order_release);
         ret = handshake_.post() && ret;
         mtx.lock();
@@ -175,7 +179,7 @@ public:
     }
 
     template <typename F>
-    bool wait_if(handle_t& h, F&& pred) {
+    bool wait_if(handle_t& h, F&& pred, std::size_t tm = invalid_value) {
         if (h == invalid()) return false;
 
         class non_mutex {
@@ -184,7 +188,7 @@ public:
             void unlock() noexcept {}
         } nm;
 
-        return h.wait_if(nm, std::forward<F>(pred));
+        return h.wait_if(nm, std::forward<F>(pred), tm);
     }
 
     void notify(handle_t& h) {
diff --git a/src/platform/waiter_wrapper.h b/src/platform/waiter_wrapper.h
index 0941676..6bcb6d3 100644
--- a/src/platform/waiter_wrapper.h
+++ b/src/platform/waiter_wrapper.h
@@ -40,8 +40,8 @@ public:
         cnt_h_ .release();
     }
 
-    bool wait(mutex_impl& mtx) {
-        return ipc::detail::condition::wait_if(mtx, [] { return true; });
+    bool wait(mutex_impl& mtx, std::size_t tm = invalid_value) {
+        return ipc::detail::condition::wait_if(mtx, [] { return true; }, tm);
     }
 };
 
@@ -100,8 +100,8 @@ public:
 
 class condition_impl : public object_impl<ipc::detail::condition> {
 public:
-    bool wait(mutex_impl& mtx) {
-        return object().wait(mtx.object());
+    bool wait(mutex_impl& mtx, std::size_t tm = invalid_value) {
+        return object().wait(mtx.object(), tm);
     }
 
     bool notify   () { return object().notify   (); }
@@ -140,9 +140,9 @@ public:
         opened_.release();
     }
 
-    bool wait() {
+    bool wait(std::size_t tm = invalid_value) {
         if (h_ == sem_helper::invalid()) return false;
-        return sem_helper::wait(h_);
+        return sem_helper::wait(h_, tm);
     }
 
     bool post(long count) {
@@ -205,9 +205,9 @@ public:
     }
 
     template <typename F>
-    bool wait_if(F&& pred) {
+    bool wait_if(F&& pred, std::size_t tm = invalid_value) {
         if (!valid()) return false;
-        return w_->wait_if(h_, std::forward<F>(pred));
+        return w_->wait_if(h_, std::forward<F>(pred), tm);
     }
 
     bool notify() {
diff --git a/src/waiter.cpp b/src/waiter.cpp
index 5ff6cd2..54e8840 100644
--- a/src/waiter.cpp
+++ b/src/waiter.cpp
@@ -43,8 +43,8 @@ bool mutex::unlock() {
 
 #include "waiter_template.inc"
 
-bool semaphore::wait() {
-    return impl(p_)->h_.wait();
+bool semaphore::wait(std::size_t tm) {
+    return impl(p_)->h_.wait(tm);
 }
 
 bool semaphore::post(long count) {
@@ -61,8 +61,8 @@ bool semaphore::post(long count) {
 
 #include "waiter_template.inc"
 
-bool condition::wait(mutex& mtx) {
-    return impl(p_)->h_.wait(impl(mtx.p_)->h_);
+bool condition::wait(mutex& mtx, std::size_t tm) {
+    return impl(p_)->h_.wait(impl(mtx.p_)->h_, tm);
 }
 
 bool condition::notify() {