From 7745a6cc4208ef3ba4190922a6e82cb0131b7206 Mon Sep 17 00:00:00 2001
From: Paul T <developer.paul.123@gmail.com>
Date: Fri, 26 Apr 2024 09:52:07 -0400
Subject: [PATCH 1/4] feat: add initial version of thread init function

Added initial version of thread initialization function.
---
 include/thread_pool/thread_pool.h | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/include/thread_pool/thread_pool.h b/include/thread_pool/thread_pool.h
index 8a8fe22..844b395 100644
--- a/include/thread_pool/thread_pool.h
+++ b/include/thread_pool/thread_pool.h
@@ -34,14 +34,20 @@ namespace dp {
                  std::is_same_v<void, std::invoke_result_t<FunctionType>>
     class thread_pool {
       public:
+        template <typename InitializationFunction = std::function<void(std::size_t)>>
+            requires std::invocable<InitializationFunction, std::size_t> &&
+                     std::is_same_v<void, std::invoke_result_t<InitializationFunction, std::size_t>>
         explicit thread_pool(
-            const unsigned int &number_of_threads = std::thread::hardware_concurrency())
+            const unsigned int &number_of_threads = std::thread::hardware_concurrency(),
+            InitializationFunction init = [](std::size_t) {})
             : tasks_(number_of_threads) {
             std::size_t current_id = 0;
             for (std::size_t i = 0; i < number_of_threads; ++i) {
                 priority_queue_.push_back(size_t(current_id));
                 try {
-                    threads_.emplace_back([&, id = current_id](const std::stop_token &stop_tok) {
+                    threads_.emplace_back([&, id = current_id,
+                                           init](const std::stop_token &stop_tok) {
+                        init(id);
                         do {
                             // wait until signaled
                             tasks_[id].signal.acquire();

From 05d5ce3ec1413dcc8faa6e7f8eef023520d4e693 Mon Sep 17 00:00:00 2001
From: Paul T <developer.paul.123@gmail.com>
Date: Fri, 26 Apr 2024 09:52:35 -0400
Subject: [PATCH 2/4] test: add unit test for thread init function

---
 test/source/thread_pool.cpp | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/test/source/thread_pool.cpp b/test/source/thread_pool.cpp
index 9fe8f4f..5c563b8 100644
--- a/test/source/thread_pool.cpp
+++ b/test/source/thread_pool.cpp
@@ -6,6 +6,7 @@
 #include <algorithm>
 #include <iostream>
 #include <numeric>
+#include <print>
 #include <random>
 #include <string>
 #include <thread>
@@ -445,3 +446,14 @@ TEST_CASE("Ensure wait_for_tasks() properly blocks current execution.") {
 
     CHECK_EQ(counter.load(), total_tasks);
 }
+
+TEST_CASE("Initialization function is called") {
+    std::atomic_int counter = 0;
+    {
+        dp::thread_pool pool(4, [&counter](std::size_t id) {
+            std::print("Thread {} initialized\n", id);
+            counter.fetch_add(1);
+        });
+    }
+    CHECK_EQ(counter.load(), 4);
+}

From 13b9c82c148d615b90293bc67d9645d0151004be Mon Sep 17 00:00:00 2001
From: Paul T <developer.paul.123@gmail.com>
Date: Fri, 26 Apr 2024 09:59:59 -0400
Subject: [PATCH 3/4] fix: <print> isn't available everywhere

---
 test/source/thread_pool.cpp | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/test/source/thread_pool.cpp b/test/source/thread_pool.cpp
index 5c563b8..275e1d4 100644
--- a/test/source/thread_pool.cpp
+++ b/test/source/thread_pool.cpp
@@ -4,9 +4,9 @@
 #include <thread_pool/version.h>
 
 #include <algorithm>
+#include <format>
 #include <iostream>
 #include <numeric>
-#include <print>
 #include <random>
 #include <string>
 #include <thread>
@@ -451,7 +451,7 @@ TEST_CASE("Initialization function is called") {
     std::atomic_int counter = 0;
     {
         dp::thread_pool pool(4, [&counter](std::size_t id) {
-            std::print("Thread {} initialized\n", id);
+            std::cout << std::format("Thread {} initialized\n", id);
             counter.fetch_add(1);
         });
     }

From 99d2e15d4f400ae025d0cb0375b1574e610f93ac Mon Sep 17 00:00:00 2001
From: Paul T <developer.paul.123@gmail.com>
Date: Fri, 26 Apr 2024 11:06:38 -0400
Subject: [PATCH 4/4] fix: <format> isn't available everywhere either...

---
 test/source/thread_pool.cpp | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/test/source/thread_pool.cpp b/test/source/thread_pool.cpp
index 275e1d4..2c008a5 100644
--- a/test/source/thread_pool.cpp
+++ b/test/source/thread_pool.cpp
@@ -4,7 +4,6 @@
 #include <thread_pool/version.h>
 
 #include <algorithm>
-#include <format>
 #include <iostream>
 #include <numeric>
 #include <random>
@@ -451,7 +450,7 @@ TEST_CASE("Initialization function is called") {
     std::atomic_int counter = 0;
     {
         dp::thread_pool pool(4, [&counter](std::size_t id) {
-            std::cout << std::format("Thread {} initialized\n", id);
+            std::cout << "Thread " << id << " initialized\n";
             counter.fetch_add(1);
         });
     }