enqueue_detach a non-void returning function

include/thread_pool/thread_pool.h

@@ -187,22 +187,26 @@ namespace dp {
         }
 
         /**
-         * @brief Enqueue a task to be executed in the thread pool that returns void.
+         * @brief Enqueue a task to be executed in the thread pool. Any return value of the function will be ignored.
          * @tparam Function An invokable type.
          * @tparam Args Argument parameter pack for Function
          * @param func The callable to be executed
          * @param args Arguments that will be passed to the function.
          */
         template <typename Function, typename... Args>
-            requires std::invocable<Function, Args...> &&
-                     std::is_same_v<void, std::invoke_result_t<Function &&, Args &&...>>
+            requires std::invocable<Function, Args...>
         void enqueue_detach(Function &&func, Args &&...args) {
             enqueue_task(
                 std::move([f = std::forward<Function>(func),
                            ... largs = std::forward<Args>(args)]() mutable -> decltype(auto) {
                     // suppress exceptions
                     try {
-                        std::invoke(f, largs...);
+                        if constexpr (std::is_same_v<void, std::invoke_result_t<Function &&, Args &&...>>) {
+                            std::invoke(f, largs...);
+                        } else {
+                            // the function returns an argument, but can be ignored
+                            std::ignore = std::invoke(f, largs...);
+                        }
                     } catch (...) {
                     }
                 }));

test/source/thread_pool.cpp

@@ -56,6 +56,29 @@ TEST_CASE("Support enqueue with void return type") {
     CHECK_EQ(value, 16);
 }
 
+TEST_CASE("Support enqueue_detach with void return type") {
+    auto value = 8;
+    {
+        dp::thread_pool pool;
+        pool.enqueue_detach([](int& x) { x *= 2; }, std::ref(value));
+    }
+    CHECK_EQ(value, 16);
+}
+
+TEST_CASE("Support enqueue_detach with non void return type") {
+    auto value = 8;
+    {
+        dp::thread_pool pool;
+        pool.enqueue_detach(
+            [](int& x) {
+                x *= 2;
+                return x;
+            },
+            std::ref(value));
+    }
+    CHECK_EQ(value, 16);
+}
+
 TEST_CASE("Ensure input params are properly passed") {
     dp::thread_pool pool(4);
     constexpr auto total_tasks = 30;