From 5378c6c3a29550cd3ccf4514e0f2793a507e4673 Mon Sep 17 00:00:00 2001
From: ITHelpDec <34002836+ITHelpDec@users.noreply.github.com>
Date: Sat, 8 Jul 2023 15:14:12 +0100
Subject: [PATCH 1/3] opt for `std::make_unique<>` over `operator new`

- see Herb Sutter's talk
- https://herbsutter.com/gotw/_102/
---
 listings/listing_9.2.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/listings/listing_9.2.cpp b/listings/listing_9.2.cpp
index bb32073..b0830b9 100644
--- a/listings/listing_9.2.cpp
+++ b/listings/listing_9.2.cpp
@@ -22,7 +22,7 @@ class function_wrapper
 public:
     template<typename F>
     function_wrapper(F&& f):
-        impl(new impl_type<F>(std::move(f)))
+        impl(std::make_unique<impl_type<F>>(std::move(f)))
     {}
 
     void call() { impl->call(); }

From a12f8ac4c83abdc1472b42e86c18e545026f4ec6 Mon Sep 17 00:00:00 2001
From: ITHelpDec <34002836+ITHelpDec@users.noreply.github.com>
Date: Sat, 8 Jul 2023 15:37:53 +0100
Subject: [PATCH 2/3] `std::result_of` -> `std::invoke_result_t`

- `std::result_of` was deprecated as of C++17, and removed in C++20
- opt for `std::invoke_result_t` in its place for all instances
- also improves brevity
---
 listings/listing_9.2.cpp | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/listings/listing_9.2.cpp b/listings/listing_9.2.cpp
index b0830b9..79b500b 100644
--- a/listings/listing_9.2.cpp
+++ b/listings/listing_9.2.cpp
@@ -48,10 +48,10 @@ class thread_pool
     std::deque<function_wrapper> work_queue;
 
     template<typename FunctionType>
-    std::future<typename std::result_of<FunctionType()>::type>
+    std::future<std::invoke_result_t<FunctionType&&>>
     submit(FunctionType f)
     {
-        typedef typename std::result_of<FunctionType()>::type result_type;
+        typedef std::invoke_result_t<FunctionType&&> result_type;
         
         std::packaged_task<result_type()> task(std::move(f));
         std::future<result_type> res(task.get_future());

From 797213f6bad2c3acc80dafe58d58aaea3088c5f8 Mon Sep 17 00:00:00 2001
From: ITHelpDec <34002836+ITHelpDec@users.noreply.github.com>
Date: Sat, 8 Jul 2023 15:47:37 +0100
Subject: [PATCH 3/3] use of `noexcept` with move(-assignment) operations

- move and move-assignment operations should not throw
---
 listings/listing_9.2.cpp | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/listings/listing_9.2.cpp b/listings/listing_9.2.cpp
index 79b500b..801e672 100644
--- a/listings/listing_9.2.cpp
+++ b/listings/listing_9.2.cpp
@@ -21,17 +21,17 @@ class function_wrapper
     };
 public:
     template<typename F>
-    function_wrapper(F&& f):
+    function_wrapper(F&& f) noexcept:
         impl(std::make_unique<impl_type<F>>(std::move(f)))
     {}
 
     void call() { impl->call(); }
 
-    function_wrapper(function_wrapper&& other):
+    function_wrapper(function_wrapper&& other) noexcept:
         impl(std::move(other.impl))
     {}
 
-    function_wrapper& operator=(function_wrapper&& other)
+    function_wrapper& operator=(function_wrapper&& other) noexcept
     {
         impl=std::move(other.impl);
         return *this;