Use std::ignore to fix unused variable warnings

Author: mutouyun

benchmark/benchmark_concur.cpp

@@ -3,6 +3,7 @@
 #include <future>
 #include <atomic>
 #include <vector>
+#include <tuple>
 
 #include "benchmark/benchmark.h"
 
@@ -18,18 +19,18 @@ void concur_queue_rtt(benchmark::State &state) {
     for (std::int64_t i = 0; !stop.load(std::memory_order_relaxed); ++i) {
       std::int64_t n {};
       while (!que[0].pop(n)) ;
-      (void)que[1].push(i);
+      std::ignore = que[1].push(i);
     }
   });
 
   for (auto _ : state) {
-    (void)que[0].push(0);
+    std::ignore = que[0].push(0);
     std::int64_t n {};
     while (!que[1].pop(n)) ;
   }
 
   stop = true;
-  (void)que[0].push(0);
+  std::ignore = que[0].push(0);
   producer.wait();
 }
 
@@ -39,7 +40,7 @@ void concur_queue_1v1(benchmark::State &state) {
   std::atomic_bool stop = false;
   auto producer = std::async(std::launch::async, [&stop, &que] {
     for (std::int64_t i = 0; !stop.load(std::memory_order_relaxed); ++i) {
-      (void)que.push(i);
+      std::ignore = que.push(i);
       std::this_thread::yield();
     }
   });
@@ -65,7 +66,7 @@ void concur_queue_NvN(benchmark::State &state) {
     prods.resize(state.threads());
     auto producer = [] {
       for (std::int64_t i = 0; run.load(std::memory_order_relaxed) > 0; ++i) {
-        (void)que.push(i);
+        std::ignore = que.push(i);
         std::this_thread::yield();
       }
     };

include/libconcur/data_model.h

@@ -8,6 +8,7 @@
 
 #include <atomic>
 #include <array>
+#include <tuple>
 #include <cstddef>
 #include <cstdint>
 
@@ -46,19 +47,19 @@ class data_model {
       typename decltype(elements)::size_type i = 0;
       LIBIMP_TRY {
         for (; i < elements.size(); ++i) {
-          (void)::LIBIMP::construct<element<value_type>>(&elements[i]);
+          std::ignore = ::LIBIMP::construct<element<value_type>>(&elements[i]);
         }
       } LIBIMP_CATCH(...) {
         for (decltype(i) k = 0; k < i; ++k) {
-          (void)::LIBIMP::destroy<element<value_type>>(&elements[k]);
+          std::ignore = ::LIBIMP::destroy<element<value_type>>(&elements[k]);
         }
         throw;
       }
     }
 
     ~data() noexcept {
       for (auto &elem : this->elements()) {
-        (void)::LIBIMP::destroy<element<value_type>>(&elem);
+        std::ignore = ::LIBIMP::destroy<element<value_type>>(&elem);
       }
     }
 
@@ -124,7 +125,7 @@ class data_model {
   ~data_model() noexcept {
     if (valid()) {
       auto sz = data_->byte_size();
-      (void)::LIBIMP::destroy<data>(data_);
+      std::ignore = ::LIBIMP::destroy<data>(data_);
       data_allocator_.deallocate(data_, sz);
     }
   }