using 'signal' to quit waiting explicitly

demo/send_recv/main.cpp

@@ -1,17 +1,24 @@
 
+#include <signal.h>
+
 #include <iostream>
 #include <string>
 #include <thread>
 #include <chrono>
+#include <atomic>
 
 #include "libipc/ipc.h"
 
 namespace {
 
+std::atomic<bool> is_quit__ {false};
+ipc::channel *ipc__ = nullptr;
+
 void do_send(int size, int interval) {
     ipc::channel ipc {"ipc", ipc::sender};
+    ipc__ = &ipc;
     std::string buffer(size, 'A');
-    while (true) {
+    while (!is_quit__.load(std::memory_order_acquire)) {
         std::cout << "send size: " << buffer.size() + 1 << "\n";
         ipc.send(buffer, 0/*tm*/);
         std::this_thread::sleep_for(std::chrono::milliseconds(interval));
@@ -20,11 +27,13 @@ void do_send(int size, int interval) {
 
 void do_recv(int interval) {
     ipc::channel ipc {"ipc", ipc::receiver};
-    while (true) {
+    ipc__ = &ipc;
+    while (!is_quit__.load(std::memory_order_acquire)) {
         ipc::buff_t recv;
         for (int k = 1; recv.empty(); ++k) {
             std::cout << "recv waiting... " << k << "\n";
             recv = ipc.recv(interval);
+            if (is_quit__.load(std::memory_order_acquire)) return;
         }
         std::cout << "recv size: " << recv.size() << "\n";
     }
@@ -34,6 +43,23 @@ void do_recv(int interval) {
 
 int main(int argc, char ** argv) {
     if (argc < 3) return -1;
+
+    auto exit = [](int) {
+        is_quit__.store(true, std::memory_order_release);
+        if (ipc__ != nullptr) ipc__->disconnect();
+    };
+    ::signal(SIGINT  , exit);
+    ::signal(SIGABRT , exit);
+    ::signal(SIGSEGV , exit);
+    ::signal(SIGTERM , exit);
+#if defined(WIN64) || defined(_WIN64) || defined(__WIN64__) || \
+    defined(WIN32) || defined(_WIN32) || defined(__WIN32__) || defined(__NT__) || \
+    defined(WINCE) || defined(_WIN32_WCE)
+    ::signal(SIGBREAK, exit);
+#else
+    ::signal(SIGHUP  , exit);
+#endif
+
     std::string mode {argv[1]};
     if (mode == "send") {
         if (argc < 4) return -1;

src/libipc/ipc.cpp

@@ -301,15 +301,13 @@ template <typename W, typename F>
 bool wait_for(W& waiter, F&& pred, std::uint64_t tm) {
     if (tm == 0) return !pred();
     for (unsigned k = 0; pred();) {
-        bool loop = true, ret = true;
-        ipc::sleep(k, [&k, &loop, &ret, &waiter, &pred, tm] {
-            ret = waiter.wait_if([&loop, &pred] {
-                    return loop = pred();
-                }, tm);
+        bool ret = true;
+        ipc::sleep(k, [&k, &ret, &waiter, &pred, tm] {
+            ret = waiter.wait_if(std::forward<F>(pred), tm);
             k   = 0;
         });
         if (!ret) return false; // timeout or fail
-        if (!loop) break;
+        if (k == 0) break; // k has been reset
     }
     return true;
 }

test/test_sync.cpp

@@ -162,6 +162,9 @@ TEST(Sync, Condition) {
     for (auto &t : test_conds) t.join();
 }
 
+/**
+ * https://stackoverflow.com/questions/51730660/is-this-a-bug-in-glibc-pthread
+*/
 TEST(Sync, ConditionRobust) {
     printf("XXXXXXXXXXXXXXXXXXXXXXXXXXXXXX 1\n");
     ipc::sync::condition cond {"test-cond"};
@@ -180,7 +183,7 @@ TEST(Sync, ConditionRobust) {
         }
         std::this_thread::sleep_for(std::chrono::seconds(1));
         printf("WWWWWWWWWWWWWWWWWWWWWWWWWWWWWW 4\n");
-        cond.notify();
+        cond.broadcast();
         printf("WWWWWWWWWWWWWWWWWWWWWWWWWWWWWW 5\n");
     }};
     printf("XXXXXXXXXXXXXXXXXXXXXXXXXXXXXX 4\n");