diff --git a/subproject/test/source/test_all_shorter_interval_cases.cpp b/subproject/test/source/test_all_shorter_interval_cases.cpp
index dfc45f1..da691ca 100644
--- a/subproject/test/source/test_all_shorter_interval_cases.cpp
+++ b/subproject/test/source/test_all_shorter_interval_cases.cpp
@@ -23,8 +23,8 @@
 #include <string_view>
 #include <utility>
 
-void reference_implementation(float x, char* buffer) { f2s_buffered(x, buffer); }
-void reference_implementation(double x, char* buffer) { d2s_buffered(x, buffer); }
+static void reference_implementation(float x, char* buffer) { f2s_buffered(x, buffer); }
+static void reference_implementation(double x, char* buffer) { d2s_buffered(x, buffer); }
 
 template <class Float, class... Args>
 static bool test_all_shorter_interval_cases_impl(Args&&... args) {
diff --git a/subproject/test/source/uniform_random_test.cpp b/subproject/test/source/uniform_random_test.cpp
index 1eb446c..80730b9 100644
--- a/subproject/test/source/uniform_random_test.cpp
+++ b/subproject/test/source/uniform_random_test.cpp
@@ -23,8 +23,8 @@
 #include <string_view>
 #include <utility>
 
-void reference_implementation(float x, char* buffer) { f2s_buffered(x, buffer); }
-void reference_implementation(double x, char* buffer) { d2s_buffered(x, buffer); }
+static void reference_implementation(float x, char* buffer) { f2s_buffered(x, buffer); }
+static void reference_implementation(double x, char* buffer) { d2s_buffered(x, buffer); }
 
 template <class Float, class TypenameString, class... Args>
 static bool uniform_random_test(std::size_t number_of_tests, TypenameString&& type_name_string,
diff --git a/subproject/test/source/verify_cache_precision.cpp b/subproject/test/source/verify_cache_precision.cpp
index 04a17c0..487ebbb 100644
--- a/subproject/test/source/verify_cache_precision.cpp
+++ b/subproject/test/source/verify_cache_precision.cpp
@@ -30,7 +30,7 @@
 #include <utility>
 #include <vector>
 
-std::ostream& operator<<(std::ostream& out, jkj::big_uint const& n) {
+static std::ostream& operator<<(std::ostream& out, jkj::big_uint const& n) {
     auto dec = n.to_decimal();
     assert(!dec.empty());
 
@@ -66,7 +66,7 @@ struct analysis_result {
 };
 
 template <class FormatTraits>
-bool analyze(std::ostream& out, std::size_t cache_bits) {
+static bool analyze(std::ostream& out, std::size_t cache_bits) {
     out << "e,bits_for_multiplication,bits_for_integer_check\n";
 
     using impl = jkj::dragonbox::detail::impl<FormatTraits>;
diff --git a/subproject/test/source/verify_log_computation.cpp b/subproject/test/source/verify_log_computation.cpp
index 4c66bcb..c9b1409 100644
--- a/subproject/test/source/verify_log_computation.cpp
+++ b/subproject/test/source/verify_log_computation.cpp
@@ -21,7 +21,7 @@
 #include <functional>
 #include <iostream>
 
-int floor_log10_pow2_precise(int e) {
+static int floor_log10_pow2_precise(int e) {
     using namespace jkj::dragonbox::detail::log;
     bool is_negative;
     if (e < 0) {
@@ -44,7 +44,7 @@ int floor_log10_pow2_precise(int e) {
     return is_negative ? -k : k - 1;
 }
 
-int floor_log10_pow2_minus_log10_4_over_3_precise(int e) {
+static int floor_log10_pow2_minus_log10_4_over_3_precise(int e) {
     e -= 2;
 
     if (e < 0) {
@@ -72,7 +72,7 @@ int floor_log10_pow2_minus_log10_4_over_3_precise(int e) {
     }
 }
 
-int floor_log2_pow10_precise(int e) {
+static int floor_log2_pow10_precise(int e) {
     bool is_negative;
     if (e < 0) {
         is_negative = true;
@@ -93,7 +93,7 @@ int floor_log2_pow10_precise(int e) {
     return is_negative ? -k : k - 1;
 }
 
-int floor_log5_pow2_precise(int e) {
+static int floor_log5_pow2_precise(int e) {
     bool is_negative;
     if (e < 0) {
         is_negative = true;
@@ -114,7 +114,7 @@ int floor_log5_pow2_precise(int e) {
     return is_negative ? -k : k - 1;
 }
 
-int floor_log5_pow2_minus_log5_3_precise(int e) {
+static int floor_log5_pow2_minus_log5_3_precise(int e) {
     if (e >= 0) {
         auto power_of_2 = jkj::big_uint::power_of_2(std::size_t(e));
         auto power_of_5_times_3 = jkj::big_uint(3);
@@ -145,7 +145,7 @@ struct verify_result {
 
 template <jkj::dragonbox::detail::log::multiply m, jkj::dragonbox::detail::log::subtract f,
           jkj::dragonbox::detail::log::shift k>
-verify_result verify(std::string_view name, std::function<int(int)> precise_calculator = nullptr) {
+static verify_result verify(std::string_view name, std::function<int(int)> precise_calculator = nullptr) {
     // Compute the maximum possible e
     constexpr auto max_exponent_upper_bound =
         std::numeric_limits<std::int32_t>::max() / std::int32_t(m);