diff --git a/.github/workflows/clang-tidy.yaml b/.github/workflows/clang-tidy.yaml
index 1d8e068777..35505e8512 100644
--- a/.github/workflows/clang-tidy.yaml
+++ b/.github/workflows/clang-tidy.yaml
@@ -17,9 +17,9 @@ jobs:
       matrix:
         include:
           - cmake_options: all-options-abiv1-preview
-            warning_limit: 490
+            warning_limit: 330
           - cmake_options: all-options-abiv2-preview
-            warning_limit: 492
+            warning_limit: 332
     env:
       CC: /usr/bin/clang-18
       CXX: /usr/bin/clang++-18
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 4a6485e3d3..a7788e32f2 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -39,6 +39,9 @@ Increment the:
 * [EXAMPLES] Deprecated semantic conventions used
   [#3905](https://github.com/open-telemetry/opentelemetry-cpp/pull/3905)
 
+* [CODE HEALTH] Fix clang-tidy misc-use-internal-linkage warnings
+  [#3600](https://github.com/open-telemetry/opentelemetry-cpp/pull/3600)
+
 Important changes:
 
 * [BUILD] Revisit EventLogger deprecation
diff --git a/api/test/baggage/baggage_test.cc b/api/test/baggage/baggage_test.cc
index be7b4ccdf4..cd19be487a 100644
--- a/api/test/baggage/baggage_test.cc
+++ b/api/test/baggage/baggage_test.cc
@@ -15,7 +15,7 @@
 
 using namespace opentelemetry::baggage;
 
-std::string header_with_custom_entries(size_t num_entries)
+static std::string header_with_custom_entries(size_t num_entries)
 {
   std::string header;
   for (size_t i = 0; i < num_entries; i++)
@@ -31,7 +31,7 @@ std::string header_with_custom_entries(size_t num_entries)
   return header;
 }
 
-std::string header_with_custom_size(size_t key_value_size, size_t num_entries)
+static std::string header_with_custom_size(size_t key_value_size, size_t num_entries)
 {
   std::string header = "";
   for (size_t i = 0; i < num_entries; i++)
diff --git a/api/test/nostd/function_ref_test.cc b/api/test/nostd/function_ref_test.cc
index 460561e765..2159e6d2ee 100644
--- a/api/test/nostd/function_ref_test.cc
+++ b/api/test/nostd/function_ref_test.cc
@@ -8,12 +8,12 @@
 
 using namespace opentelemetry::nostd;
 
-int Call(function_ref<int()> f)
+static int Call(function_ref<int()> f)
 {
   return f();
 }
 
-int Return3()
+static int Return3()
 {
   return 3;
 }
diff --git a/api/test/singleton/singleton_test.cc b/api/test/singleton/singleton_test.cc
index 36101df86f..ad945b9084 100644
--- a/api/test/singleton/singleton_test.cc
+++ b/api/test/singleton/singleton_test.cc
@@ -32,7 +32,7 @@
 
 using namespace opentelemetry;
 
-void do_something()
+static void do_something()
 {
   do_something_in_a();
   do_something_in_b();
@@ -111,33 +111,33 @@ void do_something()
 #endif /* BAZEL_BUILD */
 }
 
-int span_a_lib_count   = 0;
-int span_a_f1_count    = 0;
-int span_a_f2_count    = 0;
-int span_b_lib_count   = 0;
-int span_b_f1_count    = 0;
-int span_b_f2_count    = 0;
-int span_c_lib_count   = 0;
-int span_c_f1_count    = 0;
-int span_c_f2_count    = 0;
-int span_d_lib_count   = 0;
-int span_d_f1_count    = 0;
-int span_d_f2_count    = 0;
-int span_e_lib_count   = 0;
-int span_e_f1_count    = 0;
-int span_e_f2_count    = 0;
-int span_f_lib_count   = 0;
-int span_f_f1_count    = 0;
-int span_f_f2_count    = 0;
-int span_g_lib_count   = 0;
-int span_g_f1_count    = 0;
-int span_g_f2_count    = 0;
-int span_h_lib_count   = 0;
-int span_h_f1_count    = 0;
-int span_h_f2_count    = 0;
-int unknown_span_count = 0;
-
-void reset_counts()
+static int span_a_lib_count   = 0;
+static int span_a_f1_count    = 0;
+static int span_a_f2_count    = 0;
+static int span_b_lib_count   = 0;
+static int span_b_f1_count    = 0;
+static int span_b_f2_count    = 0;
+static int span_c_lib_count   = 0;
+static int span_c_f1_count    = 0;
+static int span_c_f2_count    = 0;
+static int span_d_lib_count   = 0;
+static int span_d_f1_count    = 0;
+static int span_d_f2_count    = 0;
+static int span_e_lib_count   = 0;
+static int span_e_f1_count    = 0;
+static int span_e_f2_count    = 0;
+static int span_f_lib_count   = 0;
+static int span_f_f1_count    = 0;
+static int span_f_f2_count    = 0;
+static int span_g_lib_count   = 0;
+static int span_g_f1_count    = 0;
+static int span_g_f2_count    = 0;
+static int span_h_lib_count   = 0;
+static int span_h_f1_count    = 0;
+static int span_h_f2_count    = 0;
+static int unknown_span_count = 0;
+
+static void reset_counts()
 {
   span_a_lib_count   = 0;
   span_a_f1_count    = 0;
@@ -331,7 +331,7 @@ class MyTracerProvider : public trace::TracerProvider
 #endif
 };
 
-void setup_otel()
+static void setup_otel()
 {
   std::shared_ptr<opentelemetry::trace::TracerProvider> provider = MyTracerProvider::Create();
 
@@ -343,7 +343,7 @@ void setup_otel()
   trace_api::Provider::SetTracerProvider(provider);
 }
 
-void cleanup_otel()
+static void cleanup_otel()
 {
   std::shared_ptr<opentelemetry::trace::TracerProvider> provider(
       new opentelemetry::trace::NoopTracerProvider());
diff --git a/exporters/ostream/src/metric_exporter.cc b/exporters/ostream/src/metric_exporter.cc
index 39f5b017e7..89e47f96af 100644
--- a/exporters/ostream/src/metric_exporter.cc
+++ b/exporters/ostream/src/metric_exporter.cc
@@ -76,7 +76,7 @@ namespace metrics
 {
 
 template <typename Container>
-inline void printVec(std::ostream &os, Container &vec)
+static inline void printVec(std::ostream &os, Container &vec)
 {
   using T = typename std::decay<decltype(*vec.begin())>::type;
   os << '[';
diff --git a/exporters/ostream/src/span_exporter.cc b/exporters/ostream/src/span_exporter.cc
index f41d33ae6c..228ca65127 100644
--- a/exporters/ostream/src/span_exporter.cc
+++ b/exporters/ostream/src/span_exporter.cc
@@ -40,7 +40,7 @@ namespace exporter
 namespace trace
 {
 
-std::ostream &operator<<(std::ostream &os, trace_api::SpanKind span_kind)
+static std::ostream &operator<<(std::ostream &os, trace_api::SpanKind span_kind)
 {
   switch (span_kind)
   {
diff --git a/exporters/otlp/test/otlp_http_exporter_test.cc b/exporters/otlp/test/otlp_http_exporter_test.cc
index 85a27022a3..3cbfa9d16c 100644
--- a/exporters/otlp/test/otlp_http_exporter_test.cc
+++ b/exporters/otlp/test/otlp_http_exporter_test.cc
@@ -56,8 +56,8 @@ static nostd::span<T, N> MakeSpan(T (&array)[N])
   return nostd::span<T, N>(array);
 }
 
-OtlpHttpClientOptions MakeOtlpHttpClientOptions(HttpRequestContentType content_type,
-                                                bool async_mode)
+static OtlpHttpClientOptions MakeOtlpHttpClientOptions(HttpRequestContentType content_type,
+                                                       bool async_mode)
 {
   std::shared_ptr<opentelemetry::sdk::common::ThreadInstrumentation> not_instrumented;
   OtlpHttpExporterOptions options;
diff --git a/exporters/otlp/test/otlp_http_log_record_exporter_test.cc b/exporters/otlp/test/otlp_http_log_record_exporter_test.cc
index f887b2372e..3fca7a06ea 100644
--- a/exporters/otlp/test/otlp_http_log_record_exporter_test.cc
+++ b/exporters/otlp/test/otlp_http_log_record_exporter_test.cc
@@ -51,8 +51,8 @@ static nostd::span<T, N> MakeSpan(T (&array)[N])
   return nostd::span<T, N>(array);
 }
 
-OtlpHttpClientOptions MakeOtlpHttpClientOptions(HttpRequestContentType content_type,
-                                                bool async_mode)
+static OtlpHttpClientOptions MakeOtlpHttpClientOptions(HttpRequestContentType content_type,
+                                                       bool async_mode)
 {
   std::shared_ptr<opentelemetry::sdk::common::ThreadInstrumentation> not_instrumented;
   OtlpHttpLogRecordExporterOptions options;
diff --git a/exporters/otlp/test/otlp_http_metric_exporter_test.cc b/exporters/otlp/test/otlp_http_metric_exporter_test.cc
index f27c186e2e..cd3b89183c 100644
--- a/exporters/otlp/test/otlp_http_metric_exporter_test.cc
+++ b/exporters/otlp/test/otlp_http_metric_exporter_test.cc
@@ -72,8 +72,8 @@ static IntegerType JsonToInteger(nlohmann::json value)
   return value.get<IntegerType>();
 }
 
-OtlpHttpClientOptions MakeOtlpHttpClientOptions(HttpRequestContentType content_type,
-                                                bool async_mode)
+static OtlpHttpClientOptions MakeOtlpHttpClientOptions(HttpRequestContentType content_type,
+                                                       bool async_mode)
 {
   std::shared_ptr<opentelemetry::sdk::common::ThreadInstrumentation> not_instrumented;
   OtlpHttpMetricExporterOptions options;
diff --git a/exporters/prometheus/src/exporter_options.cc b/exporters/prometheus/src/exporter_options.cc
index 0798f47cf9..a713cf3c2c 100644
--- a/exporters/prometheus/src/exporter_options.cc
+++ b/exporters/prometheus/src/exporter_options.cc
@@ -13,7 +13,7 @@ namespace exporter
 namespace metrics
 {
 
-inline const std::string GetPrometheusDefaultHttpEndpoint()
+static inline const std::string GetPrometheusDefaultHttpEndpoint()
 {
   constexpr char kPrometheusEndpointEnv[]     = "PROMETHEUS_EXPORTER_ENDPOINT";
   constexpr char kPrometheusEndpointDefault[] = "localhost:9464";
@@ -25,7 +25,7 @@ inline const std::string GetPrometheusDefaultHttpEndpoint()
   return exists ? endpoint : kPrometheusEndpointDefault;
 }
 
-inline bool GetPrometheusWithoutOtelScope()
+static inline bool GetPrometheusWithoutOtelScope()
 {
   constexpr char kPrometheusWithoutOtelScope[] = "OTEL_CPP_PROMETHEUS_EXPORTER_WITHOUT_OTEL_SCOPE";
 
@@ -36,7 +36,7 @@ inline bool GetPrometheusWithoutOtelScope()
   return exists ? setting : false;
 }
 
-inline bool GetPrometheusPopulateTargetInfo()
+static inline bool GetPrometheusPopulateTargetInfo()
 {
   constexpr char kPrometheusPopulateTargetInfo[] =
       "OTEL_CPP_PROMETHEUS_EXPORTER_POPULATE_TARGET_INFO";
@@ -48,7 +48,7 @@ inline bool GetPrometheusPopulateTargetInfo()
   return exists ? setting : true;
 }
 
-inline bool GetPrometheusWithoutUnits()
+static inline bool GetPrometheusWithoutUnits()
 {
   constexpr char kPrometheusWithoutUnits[] = "OTEL_CPP_PROMETHEUS_EXPORTER_WITHOUT_UNITS";
   bool setting{};
@@ -58,7 +58,7 @@ inline bool GetPrometheusWithoutUnits()
   return exists ? setting : false;
 }
 
-inline bool GetPrometheusWithoutTypeSuffix()
+static inline bool GetPrometheusWithoutTypeSuffix()
 {
   constexpr char kPrometheusWithoutTypeSuffix[] =
       "OTEL_CPP_PROMETHEUS_EXPORTER_WITHOUT_TYPE_SUFFIX";
diff --git a/exporters/prometheus/test/exporter_utils_test.cc b/exporters/prometheus/test/exporter_utils_test.cc
index 4ad329f0ec..b5dcd554fe 100644
--- a/exporters/prometheus/test/exporter_utils_test.cc
+++ b/exporters/prometheus/test/exporter_utils_test.cc
@@ -79,12 +79,12 @@ class SanitizeNameTester
 }  // namespace exporter
 
 template <typename T>
-void assert_basic(prometheus_client::MetricFamily &metric,
-                  const std::string &expected_name,
-                  const std::string &description,
-                  prometheus_client::MetricType type,
-                  size_t label_num,
-                  std::vector<T> vals)
+static void assert_basic(prometheus_client::MetricFamily &metric,
+                         const std::string &expected_name,
+                         const std::string &description,
+                         prometheus_client::MetricType type,
+                         size_t label_num,
+                         std::vector<T> vals)
 {
   ASSERT_EQ(metric.name, expected_name);  // name sanitized
   ASSERT_EQ(metric.help, description);    // description not changed
@@ -130,9 +130,9 @@ void assert_basic(prometheus_client::MetricFamily &metric,
   }
 }
 
-void assert_histogram(prometheus_client::MetricFamily &metric,
-                      const std::list<double> &boundaries,
-                      std::vector<int> correct)
+static void assert_histogram(prometheus_client::MetricFamily &metric,
+                             const std::list<double> &boundaries,
+                             std::vector<int> correct)
 {
   int cumulative_count = 0;
   auto buckets         = metric.metric[0].histogram.bucket;
diff --git a/exporters/zipkin/src/recordable.cc b/exporters/zipkin/src/recordable.cc
index 7152e7c92b..24325ffd24 100644
--- a/exporters/zipkin/src/recordable.cc
+++ b/exporters/zipkin/src/recordable.cc
@@ -70,9 +70,9 @@ void Recordable::SetIdentity(const trace_api::SpanContext &span_context,
   span_["traceId"] = std::string(trace_id_lower_base16, 32);
 }
 
-void PopulateAttribute(nlohmann::json &attribute,
-                       nostd::string_view key,
-                       const common::AttributeValue &value)
+static void PopulateAttribute(nlohmann::json &attribute,
+                              nostd::string_view key,
+                              const common::AttributeValue &value)
 {
   // Assert size of variant to ensure that this method gets updated if the variant
   // definition changes
diff --git a/exporters/zipkin/test/zipkin_exporter_test.cc b/exporters/zipkin/test/zipkin_exporter_test.cc
index acb0db5402..36a78edf9c 100644
--- a/exporters/zipkin/test/zipkin_exporter_test.cc
+++ b/exporters/zipkin/test/zipkin_exporter_test.cc
@@ -101,7 +101,7 @@ class IsValidMessageMatcher
   std::string trace_id_;
 };
 
-PolymorphicMatcher<IsValidMessageMatcher> IsValidMessage(const std::string &trace_id)
+static PolymorphicMatcher<IsValidMessageMatcher> IsValidMessage(const std::string &trace_id)
 {
   return MakePolymorphicMatcher(IsValidMessageMatcher(trace_id));
 }
diff --git a/ext/src/http/client/curl/http_client_curl.cc b/ext/src/http/client/curl/http_client_curl.cc
index 7c5ddd19e8..3a25e82181 100644
--- a/ext/src/http/client/curl/http_client_curl.cc
+++ b/ext/src/http/client/curl/http_client_curl.cc
@@ -67,7 +67,7 @@ nostd::shared_ptr<HttpCurlGlobalInitializer> HttpCurlGlobalInitializer::GetInsta
 #ifdef ENABLE_OTLP_COMPRESSION_PREVIEW
 // Original source:
 // https://stackoverflow.com/questions/12398377/is-it-possible-to-have-zlib-read-from-and-write-to-the-same-memory-buffer/12412863#12412863
-int deflateInPlace(z_stream *strm, unsigned char *buf, uint32_t len, uint32_t *max_len)
+static int deflateInPlace(z_stream *strm, unsigned char *buf, uint32_t len, uint32_t *max_len)
 {
   // must be large enough to hold zlib or gzip header (if any) and one more byte -- 11 works for the
   // worst case here, but if gzip encoding is used and a deflateSetHeader() call is inserted in this
diff --git a/ext/test/w3c_tracecontext_http_test_server/main.cc b/ext/test/w3c_tracecontext_http_test_server/main.cc
index 57edb0860b..adb5ddbfc0 100644
--- a/ext/test/w3c_tracecontext_http_test_server/main.cc
+++ b/ext/test/w3c_tracecontext_http_test_server/main.cc
@@ -138,7 +138,7 @@ class NoopEventHandler : public http_client::EventHandler
 }  // namespace
 
 // Sends an HTTP POST request to the given url, with the given body.
-void send_request(curl::HttpClient &client, const std::string &url, const std::string &body)
+static void send_request(curl::HttpClient &client, const std::string &url, const std::string &body)
 {
   static std::shared_ptr<http_client::EventHandler> handler(new NoopEventHandler());
 
diff --git a/functional/otlp/func_grpc_main.cc b/functional/otlp/func_grpc_main.cc
index bd51b6a85a..d7082c2e6b 100644
--- a/functional/otlp/func_grpc_main.cc
+++ b/functional/otlp/func_grpc_main.cc
@@ -47,15 +47,15 @@ enum class TestMode : std::uint8_t
   kHttps
 };
 
-bool opt_help   = false;
-bool opt_list   = false;
-bool opt_debug  = false;
-bool opt_secure = false;
+static bool opt_help   = false;
+static bool opt_list   = false;
+static bool opt_debug  = false;
+static bool opt_secure = false;
 // HTTPS by default
-std::string opt_endpoint = "https://127.0.0.1:4317";
-std::string opt_cert_dir;
-std::string opt_test_name;
-TestMode opt_mode = TestMode::kNone;
+static std::string opt_endpoint = "https://127.0.0.1:4317";
+static std::string opt_cert_dir;
+static std::string opt_test_name;
+static TestMode opt_mode = TestMode::kNone;
 
 /*
   Log parsing
@@ -79,9 +79,9 @@ struct TestResult
   }
 };
 
-struct TestResult g_test_result;
+static struct TestResult g_test_result;
 
-void parse_error_msg(TestResult *result, const std::string &msg)
+static void parse_error_msg(TestResult *result, const std::string &msg)
 {
   static std::string connection_failed("failed to connect to all addresses");
 
@@ -112,11 +112,11 @@ void parse_error_msg(TestResult *result, const std::string &msg)
   }
 }
 
-void parse_warning_msg(TestResult * /* result */, const std::string & /* msg */) {}
+static void parse_warning_msg(TestResult * /* result */, const std::string & /* msg */) {}
 
-void parse_info_msg(TestResult * /* result */, const std::string & /* msg */) {}
+static void parse_info_msg(TestResult * /* result */, const std::string & /* msg */) {}
 
-void parse_debug_msg(TestResult *result, const std::string &msg)
+static void parse_debug_msg(TestResult *result, const std::string &msg)
 {
   static std::string export_success("Export 1 trace span(s) success");
 
@@ -164,7 +164,7 @@ class TestLogHandler : public opentelemetry::sdk::common::internal_log::LogHandl
   }
 };
 
-void init(const otlp::OtlpGrpcExporterOptions &opts)
+static void init(const otlp::OtlpGrpcExporterOptions &opts)
 {
   // Create OTLP exporter instance
   auto exporter  = otlp::OtlpGrpcExporterFactory::Create(opts);
@@ -175,7 +175,7 @@ void init(const otlp::OtlpGrpcExporterOptions &opts)
   trace_sdk::Provider::SetTracerProvider(provider);
 }
 
-void payload()
+static void payload()
 {
   static const nostd::string_view k_tracer_name("func_test");
   static const nostd::string_view k_span_name("func_grpc_main");
@@ -189,13 +189,13 @@ void payload()
   span->End();
 }
 
-void cleanup()
+static void cleanup()
 {
   std::shared_ptr<opentelemetry::trace::TracerProvider> none;
   trace_sdk::Provider::SetTracerProvider(none);
 }
 
-void instrumented_payload(const otlp::OtlpGrpcExporterOptions &opts)
+static void instrumented_payload(const otlp::OtlpGrpcExporterOptions &opts)
 {
   g_test_result.reset();
   init(opts);
@@ -203,7 +203,7 @@ void instrumented_payload(const otlp::OtlpGrpcExporterOptions &opts)
   cleanup();
 }
 
-void usage(FILE *out)
+static void usage(FILE *out)
 {
   static const char *msg =
       "Usage: func_otlp_grpc [options] test_name\n"
@@ -219,7 +219,7 @@ void usage(FILE *out)
   fprintf(out, "%s", msg);
 }
 
-int parse_args(int argc, char *argv[])
+static int parse_args(int argc, char *argv[])
 {
   int remaining_argc    = argc;
   char **remaining_argv = argv;
@@ -320,20 +320,22 @@ struct test_case
   test_func_t m_func;
 };
 
-int test_basic();
+static int test_basic();
 
-int test_cert_not_found();
-int test_cert_invalid();
-int test_cert_unreadable();
-int test_client_cert_not_found();
-int test_client_cert_invalid();
-int test_client_cert_unreadable();
-int test_client_cert_no_key();
-int test_client_key_not_found();
-int test_client_key_invalid();
-int test_client_key_unreadable();
+static int test_cert_not_found();
+static int test_cert_invalid();
+static int test_cert_unreadable();
 
-int test_mtls_ok();
+#ifdef ENABLE_OTLP_GRPC_SSL_MTLS_PREVIEW
+static int test_client_cert_not_found();
+static int test_client_cert_invalid();
+static int test_client_cert_unreadable();
+static int test_client_cert_no_key();
+static int test_client_key_not_found();
+static int test_client_key_invalid();
+static int test_client_key_unreadable();
+static int test_mtls_ok();
+#endif  // ENABLE_OTLP_GRPC_SSL_MTLS_PREVIEW
 
 static const test_case all_tests[] = {{"basic", test_basic},
                                       {"cert-not-found", test_cert_not_found},
@@ -362,7 +364,7 @@ void list_test_cases()
   }
 }
 
-int run_test_case(const std::string &name)
+static int run_test_case(const std::string &name)
 {
   const test_case *current = all_tests;
 
@@ -424,7 +426,7 @@ int main(int argc, char *argv[])
   return rc;
 }
 
-void set_common_opts(otlp::OtlpGrpcExporterOptions &opts)
+static void set_common_opts(otlp::OtlpGrpcExporterOptions &opts)
 {
   opts.endpoint            = opt_endpoint;
   opts.timeout             = std::chrono::milliseconds{100};
@@ -436,7 +438,7 @@ void set_common_opts(otlp::OtlpGrpcExporterOptions &opts)
 #endif
 }
 
-int expect_connection_failed()
+static int expect_connection_failed()
 {
   if (g_test_result.found_export_error &&
       (g_test_result.found_connection_failed || g_test_result.deadline_exceeded ||
@@ -447,7 +449,7 @@ int expect_connection_failed()
   return TEST_FAILED;
 }
 
-int expect_success()
+static int expect_success()
 {
   if (g_test_result.found_export_success)
   {
@@ -456,7 +458,7 @@ int expect_success()
   return TEST_FAILED;
 }
 
-int expect_export_failed()
+static int expect_export_failed()
 {
   /*
     Can not test exact root cause:
@@ -473,7 +475,7 @@ int expect_export_failed()
   return TEST_FAILED;
 }
 
-int test_basic()
+static int test_basic()
 {
   otlp::OtlpGrpcExporterOptions opts;
 
@@ -504,7 +506,7 @@ int test_basic()
   return expect_connection_failed();
 }
 
-int test_cert_not_found()
+static int test_cert_not_found()
 {
   otlp::OtlpGrpcExporterOptions opts;
 
@@ -531,7 +533,7 @@ int test_cert_not_found()
   return expect_connection_failed();
 }
 
-int test_cert_invalid()
+static int test_cert_invalid()
 {
   otlp::OtlpGrpcExporterOptions opts;
 
@@ -558,7 +560,7 @@ int test_cert_invalid()
   return expect_connection_failed();
 }
 
-int test_cert_unreadable()
+static int test_cert_unreadable()
 {
   otlp::OtlpGrpcExporterOptions opts;
 
@@ -586,7 +588,7 @@ int test_cert_unreadable()
 }
 
 #ifdef ENABLE_OTLP_GRPC_SSL_MTLS_PREVIEW
-int test_client_cert_not_found()
+static int test_client_cert_not_found()
 {
   otlp::OtlpGrpcExporterOptions opts;
 
@@ -614,7 +616,7 @@ int test_client_cert_not_found()
   return expect_connection_failed();
 }
 
-int test_client_cert_invalid()
+static int test_client_cert_invalid()
 {
   otlp::OtlpGrpcExporterOptions opts;
 
@@ -642,7 +644,7 @@ int test_client_cert_invalid()
   return expect_connection_failed();
 }
 
-int test_client_cert_unreadable()
+static int test_client_cert_unreadable()
 {
   otlp::OtlpGrpcExporterOptions opts;
 
@@ -670,7 +672,7 @@ int test_client_cert_unreadable()
   return expect_connection_failed();
 }
 
-int test_client_cert_no_key()
+static int test_client_cert_no_key()
 {
   otlp::OtlpGrpcExporterOptions opts;
 
@@ -698,7 +700,7 @@ int test_client_cert_no_key()
   return expect_connection_failed();
 }
 
-int test_client_key_not_found()
+static int test_client_key_not_found()
 {
   otlp::OtlpGrpcExporterOptions opts;
 
@@ -727,7 +729,7 @@ int test_client_key_not_found()
   return expect_connection_failed();
 }
 
-int test_client_key_invalid()
+static int test_client_key_invalid()
 {
   otlp::OtlpGrpcExporterOptions opts;
 
@@ -756,7 +758,7 @@ int test_client_key_invalid()
   return expect_connection_failed();
 }
 
-int test_client_key_unreadable()
+static int test_client_key_unreadable()
 {
   otlp::OtlpGrpcExporterOptions opts;
 
@@ -785,7 +787,7 @@ int test_client_key_unreadable()
   return expect_connection_failed();
 }
 
-int test_mtls_ok()
+static int test_mtls_ok()
 {
   otlp::OtlpGrpcExporterOptions opts;
 
diff --git a/functional/otlp/func_http_main.cc b/functional/otlp/func_http_main.cc
index 874c8bec04..fed702e9cc 100644
--- a/functional/otlp/func_http_main.cc
+++ b/functional/otlp/func_http_main.cc
@@ -46,15 +46,15 @@ enum test_mode : std::uint8_t
   MODE_HTTPS
 };
 
-bool opt_help   = false;
-bool opt_list   = false;
-bool opt_debug  = false;
-bool opt_secure = false;
+static bool opt_help   = false;
+static bool opt_list   = false;
+static bool opt_debug  = false;
+static bool opt_secure = false;
 // HTTPS by default
-std::string opt_endpoint = "https://localhost:4318/v1/traces";
-std::string opt_cert_dir;
-std::string opt_test_name;
-test_mode opt_mode = MODE_NONE;
+static std::string opt_endpoint = "https://localhost:4318/v1/traces";
+static std::string opt_cert_dir;
+static std::string opt_test_name;
+static test_mode opt_mode = MODE_NONE;
 
 /*
   Log parsing
@@ -82,9 +82,9 @@ struct TestResult
   }
 };
 
-struct TestResult g_test_result;
+static struct TestResult g_test_result;
 
-void parse_error_msg(TestResult *result, const std::string &msg)
+static void parse_error_msg(TestResult *result, const std::string &msg)
 {
   static std::string connection_failed("Session state: connection failed.");
 
@@ -129,11 +129,11 @@ void parse_error_msg(TestResult *result, const std::string &msg)
   }
 }
 
-void parse_warning_msg(TestResult * /* result */, const std::string & /* msg */) {}
+static void parse_warning_msg(TestResult * /* result */, const std::string & /* msg */) {}
 
-void parse_info_msg(TestResult * /* result */, const std::string & /* msg */) {}
+static void parse_info_msg(TestResult * /* result */, const std::string & /* msg */) {}
 
-void parse_debug_msg(TestResult *result, const std::string &msg)
+static void parse_debug_msg(TestResult *result, const std::string &msg)
 {
   static std::string export_success("Export 1 trace span(s) success");
 
@@ -181,7 +181,7 @@ class TestLogHandler : public opentelemetry::sdk::common::internal_log::LogHandl
   }
 };
 
-void init(const otlp::OtlpHttpExporterOptions &opts)
+static void init(const otlp::OtlpHttpExporterOptions &opts)
 {
   // Create OTLP exporter instance
   auto exporter  = otlp::OtlpHttpExporterFactory::Create(opts);
@@ -192,7 +192,7 @@ void init(const otlp::OtlpHttpExporterOptions &opts)
   trace_sdk::Provider::SetTracerProvider(provider);
 }
 
-void payload()
+static void payload()
 {
   static const nostd::string_view k_tracer_name("func_test");
   static const nostd::string_view k_span_name("func_http_main");
@@ -206,13 +206,13 @@ void payload()
   span->End();
 }
 
-void cleanup()
+static void cleanup()
 {
   std::shared_ptr<opentelemetry::trace::TracerProvider> none;
   trace_sdk::Provider::SetTracerProvider(none);
 }
 
-void instrumented_payload(const otlp::OtlpHttpExporterOptions &opts)
+static void instrumented_payload(const otlp::OtlpHttpExporterOptions &opts)
 {
   g_test_result.reset();
   init(opts);
@@ -220,7 +220,7 @@ void instrumented_payload(const otlp::OtlpHttpExporterOptions &opts)
   cleanup();
 }
 
-void usage(FILE *out)
+static void usage(FILE *out)
 {
   static const char *msg =
       "Usage: func_otlp_http [options] test_name\n"
@@ -236,7 +236,7 @@ void usage(FILE *out)
   fprintf(out, "%s", msg);
 }
 
-int parse_args(int argc, char *argv[])
+static int parse_args(int argc, char *argv[])
 {
   int remaining_argc    = argc;
   char **remaining_argv = argv;
@@ -337,49 +337,49 @@ struct test_case
   test_func_t m_func;
 };
 
-int test_basic();
-
-int test_cert_not_found();
-int test_cert_invalid();
-int test_cert_unreadable();
-int test_cert_ok();
-int test_client_cert_not_found();
-int test_client_cert_invalid();
-int test_client_cert_unreadable();
-int test_client_cert_no_key();
-int test_client_key_not_found();
-int test_client_key_invalid();
-int test_client_key_unreadable();
-int test_client_key_ok();
-
-int test_min_tls_unknown();
-int test_min_tls_10();
-int test_min_tls_11();
-int test_min_tls_12();
-int test_min_tls_13();
-int test_max_tls_unknown();
-int test_max_tls_10();
-int test_max_tls_11();
-int test_max_tls_12();
-int test_max_tls_13();
-int test_range_tls_10();
-int test_range_tls_11();
-int test_range_tls_12();
-int test_range_tls_13();
-int test_range_tls_10_11();
-int test_range_tls_10_12();
-int test_range_tls_10_13();
-int test_range_tls_11_10();
-int test_range_tls_11_12();
-int test_range_tls_11_13();
-int test_range_tls_12_10();
-int test_range_tls_12_11();
-int test_range_tls_12_13();
-int test_range_tls_13_10();
-int test_range_tls_13_11();
-int test_range_tls_13_12();
-
-int test_gzip_compression();
+static int test_basic();
+
+static int test_cert_not_found();
+static int test_cert_invalid();
+static int test_cert_unreadable();
+static int test_cert_ok();
+static int test_client_cert_not_found();
+static int test_client_cert_invalid();
+static int test_client_cert_unreadable();
+static int test_client_cert_no_key();
+static int test_client_key_not_found();
+static int test_client_key_invalid();
+static int test_client_key_unreadable();
+static int test_client_key_ok();
+
+static int test_min_tls_unknown();
+static int test_min_tls_10();
+static int test_min_tls_11();
+static int test_min_tls_12();
+static int test_min_tls_13();
+static int test_max_tls_unknown();
+static int test_max_tls_10();
+static int test_max_tls_11();
+static int test_max_tls_12();
+static int test_max_tls_13();
+static int test_range_tls_10();
+static int test_range_tls_11();
+static int test_range_tls_12();
+static int test_range_tls_13();
+static int test_range_tls_10_11();
+static int test_range_tls_10_12();
+static int test_range_tls_10_13();
+static int test_range_tls_11_10();
+static int test_range_tls_11_12();
+static int test_range_tls_11_13();
+static int test_range_tls_12_10();
+static int test_range_tls_12_11();
+static int test_range_tls_12_13();
+static int test_range_tls_13_10();
+static int test_range_tls_13_11();
+static int test_range_tls_13_12();
+
+static int test_gzip_compression();
 
 static const test_case all_tests[] = {{"basic", test_basic},
                                       {"cert-not-found", test_cert_not_found},
@@ -423,7 +423,7 @@ static const test_case all_tests[] = {{"basic", test_basic},
                                       {"gzip-compression", test_gzip_compression},
                                       {"", nullptr}};
 
-void list_test_cases()
+static void list_test_cases()
 {
   const test_case *current = all_tests;
 
@@ -434,7 +434,7 @@ void list_test_cases()
   }
 }
 
-int run_test_case(const std::string &name)
+static int run_test_case(const std::string &name)
 {
   const test_case *current = all_tests;
 
@@ -496,7 +496,7 @@ int main(int argc, char *argv[])
   return rc;
 }
 
-void set_common_opts(otlp::OtlpHttpExporterOptions &opts)
+static void set_common_opts(otlp::OtlpHttpExporterOptions &opts)
 {
   opts.url = opt_endpoint;
 
@@ -511,7 +511,7 @@ void set_common_opts(otlp::OtlpHttpExporterOptions &opts)
 #endif
 }
 
-int expect_connection_failed()
+static int expect_connection_failed()
 {
   if (g_test_result.found_export_error && g_test_result.found_connection_failed)
   {
@@ -520,7 +520,7 @@ int expect_connection_failed()
   return TEST_FAILED;
 }
 
-int expect_success()
+static int expect_success()
 {
   if (g_test_result.found_export_success)
   {
@@ -529,7 +529,8 @@ int expect_success()
   return TEST_FAILED;
 }
 
-int expect_request_send_failed()
+#if 0
+static int expect_request_send_failed()
 {
   if (g_test_result.found_export_error && g_test_result.found_request_send_failure)
   {
@@ -537,8 +538,9 @@ int expect_request_send_failed()
   }
   return TEST_FAILED;
 }
+#endif
 
-int expect_unknown_min_tls()
+static int expect_unknown_min_tls()
 {
   if (g_test_result.found_export_error && g_test_result.found_unknown_min_tls)
   {
@@ -547,7 +549,7 @@ int expect_unknown_min_tls()
   return TEST_FAILED;
 }
 
-int expect_unknown_max_tls()
+static int expect_unknown_max_tls()
 {
   if (g_test_result.found_export_error && g_test_result.found_unknown_max_tls)
   {
@@ -556,7 +558,7 @@ int expect_unknown_max_tls()
   return TEST_FAILED;
 }
 
-int expect_export_failed()
+static int expect_export_failed()
 {
   /*
     Can not test exact root cause:
@@ -573,7 +575,7 @@ int expect_export_failed()
   return TEST_FAILED;
 }
 
-int test_basic()
+static int test_basic()
 {
   otlp::OtlpHttpExporterOptions opts;
 
@@ -604,7 +606,7 @@ int test_basic()
   return expect_connection_failed();
 }
 
-int test_cert_not_found()
+static int test_cert_not_found()
 {
   otlp::OtlpHttpExporterOptions opts;
 
@@ -631,7 +633,7 @@ int test_cert_not_found()
   return expect_connection_failed();
 }
 
-int test_cert_invalid()
+static int test_cert_invalid()
 {
   otlp::OtlpHttpExporterOptions opts;
 
@@ -658,7 +660,7 @@ int test_cert_invalid()
   return expect_connection_failed();
 }
 
-int test_cert_unreadable()
+static int test_cert_unreadable()
 {
   otlp::OtlpHttpExporterOptions opts;
 
@@ -685,7 +687,7 @@ int test_cert_unreadable()
   return expect_connection_failed();
 }
 
-int test_cert_ok()
+static int test_cert_ok()
 {
   otlp::OtlpHttpExporterOptions opts;
 
@@ -717,7 +719,7 @@ int test_cert_ok()
   return expect_success();
 }
 
-int test_client_cert_not_found()
+static int test_client_cert_not_found()
 {
   otlp::OtlpHttpExporterOptions opts;
 
@@ -745,7 +747,7 @@ int test_client_cert_not_found()
   return expect_connection_failed();
 }
 
-int test_client_cert_invalid()
+static int test_client_cert_invalid()
 {
   otlp::OtlpHttpExporterOptions opts;
 
@@ -773,7 +775,7 @@ int test_client_cert_invalid()
   return expect_connection_failed();
 }
 
-int test_client_cert_unreadable()
+static int test_client_cert_unreadable()
 {
   otlp::OtlpHttpExporterOptions opts;
 
@@ -801,7 +803,7 @@ int test_client_cert_unreadable()
   return expect_connection_failed();
 }
 
-int test_client_cert_no_key()
+static int test_client_cert_no_key()
 {
   otlp::OtlpHttpExporterOptions opts;
 
@@ -829,7 +831,7 @@ int test_client_cert_no_key()
   return expect_connection_failed();
 }
 
-int test_client_key_not_found()
+static int test_client_key_not_found()
 {
   otlp::OtlpHttpExporterOptions opts;
 
@@ -858,7 +860,7 @@ int test_client_key_not_found()
   return expect_connection_failed();
 }
 
-int test_client_key_invalid()
+static int test_client_key_invalid()
 {
   otlp::OtlpHttpExporterOptions opts;
 
@@ -887,7 +889,7 @@ int test_client_key_invalid()
   return expect_connection_failed();
 }
 
-int test_client_key_unreadable()
+static int test_client_key_unreadable()
 {
   otlp::OtlpHttpExporterOptions opts;
 
@@ -916,7 +918,7 @@ int test_client_key_unreadable()
   return expect_connection_failed();
 }
 
-int test_client_key_ok()
+static int test_client_key_ok()
 {
   otlp::OtlpHttpExporterOptions opts;
 
@@ -950,7 +952,7 @@ int test_client_key_ok()
   return expect_success();
 }
 
-int test_min_tls_unknown()
+static int test_min_tls_unknown()
 {
   otlp::OtlpHttpExporterOptions opts;
 
@@ -980,7 +982,7 @@ int test_min_tls_unknown()
   return expect_unknown_min_tls();
 }
 
-int test_min_tls_10()
+static int test_min_tls_10()
 {
   otlp::OtlpHttpExporterOptions opts;
 
@@ -1015,7 +1017,7 @@ int test_min_tls_10()
   return expect_unknown_min_tls();
 }
 
-int test_min_tls_11()
+static int test_min_tls_11()
 {
   otlp::OtlpHttpExporterOptions opts;
 
@@ -1050,7 +1052,7 @@ int test_min_tls_11()
   return expect_unknown_min_tls();
 }
 
-int test_min_tls_12()
+static int test_min_tls_12()
 {
   otlp::OtlpHttpExporterOptions opts;
 
@@ -1085,7 +1087,7 @@ int test_min_tls_12()
   return expect_success();
 }
 
-int test_min_tls_13()
+static int test_min_tls_13()
 {
   otlp::OtlpHttpExporterOptions opts;
 
@@ -1120,7 +1122,7 @@ int test_min_tls_13()
   return expect_success();
 }
 
-int test_max_tls_unknown()
+static int test_max_tls_unknown()
 {
   otlp::OtlpHttpExporterOptions opts;
 
@@ -1150,7 +1152,7 @@ int test_max_tls_unknown()
   return expect_unknown_max_tls();
 }
 
-int test_max_tls_10()
+static int test_max_tls_10()
 {
   otlp::OtlpHttpExporterOptions opts;
 
@@ -1186,7 +1188,7 @@ int test_max_tls_10()
   return expect_unknown_max_tls();
 }
 
-int test_max_tls_11()
+static int test_max_tls_11()
 {
   otlp::OtlpHttpExporterOptions opts;
 
@@ -1222,7 +1224,7 @@ int test_max_tls_11()
   return expect_unknown_max_tls();
 }
 
-int test_max_tls_12()
+static int test_max_tls_12()
 {
   otlp::OtlpHttpExporterOptions opts;
 
@@ -1257,7 +1259,7 @@ int test_max_tls_12()
   return expect_success();
 }
 
-int test_max_tls_13()
+static int test_max_tls_13()
 {
   otlp::OtlpHttpExporterOptions opts;
 
@@ -1292,7 +1294,7 @@ int test_max_tls_13()
   return expect_success();
 }
 
-int test_range_tls_10()
+static int test_range_tls_10()
 {
   otlp::OtlpHttpExporterOptions opts;
 
@@ -1329,7 +1331,7 @@ int test_range_tls_10()
   return expect_unknown_min_tls();
 }
 
-int test_range_tls_11()
+static int test_range_tls_11()
 {
   otlp::OtlpHttpExporterOptions opts;
 
@@ -1366,7 +1368,7 @@ int test_range_tls_11()
   return expect_unknown_min_tls();
 }
 
-int test_range_tls_12()
+static int test_range_tls_12()
 {
   otlp::OtlpHttpExporterOptions opts;
 
@@ -1402,7 +1404,7 @@ int test_range_tls_12()
   return expect_success();
 }
 
-int test_range_tls_13()
+static int test_range_tls_13()
 {
   otlp::OtlpHttpExporterOptions opts;
 
@@ -1438,7 +1440,7 @@ int test_range_tls_13()
   return expect_success();
 }
 
-int test_range_tls_10_11()
+static int test_range_tls_10_11()
 {
   otlp::OtlpHttpExporterOptions opts;
 
@@ -1475,7 +1477,7 @@ int test_range_tls_10_11()
   return expect_unknown_min_tls();
 }
 
-int test_range_tls_10_12()
+static int test_range_tls_10_12()
 {
   otlp::OtlpHttpExporterOptions opts;
 
@@ -1511,7 +1513,7 @@ int test_range_tls_10_12()
   return expect_unknown_min_tls();
 }
 
-int test_range_tls_10_13()
+static int test_range_tls_10_13()
 {
   otlp::OtlpHttpExporterOptions opts;
 
@@ -1547,7 +1549,7 @@ int test_range_tls_10_13()
   return expect_unknown_min_tls();
 }
 
-int test_range_tls_11_10()
+static int test_range_tls_11_10()
 {
   otlp::OtlpHttpExporterOptions opts;
 
@@ -1579,7 +1581,7 @@ int test_range_tls_11_10()
   return expect_connection_failed();
 }
 
-int test_range_tls_11_12()
+static int test_range_tls_11_12()
 {
   otlp::OtlpHttpExporterOptions opts;
 
@@ -1615,7 +1617,7 @@ int test_range_tls_11_12()
   return expect_unknown_min_tls();
 }
 
-int test_range_tls_11_13()
+static int test_range_tls_11_13()
 {
   otlp::OtlpHttpExporterOptions opts;
 
@@ -1651,7 +1653,7 @@ int test_range_tls_11_13()
   return expect_unknown_min_tls();
 }
 
-int test_range_tls_12_10()
+static int test_range_tls_12_10()
 {
   otlp::OtlpHttpExporterOptions opts;
 
@@ -1683,7 +1685,7 @@ int test_range_tls_12_10()
   return expect_connection_failed();
 }
 
-int test_range_tls_12_11()
+static int test_range_tls_12_11()
 {
   otlp::OtlpHttpExporterOptions opts;
 
@@ -1715,7 +1717,7 @@ int test_range_tls_12_11()
   return expect_connection_failed();
 }
 
-int test_range_tls_12_13()
+static int test_range_tls_12_13()
 {
   otlp::OtlpHttpExporterOptions opts;
 
@@ -1751,7 +1753,7 @@ int test_range_tls_12_13()
   return expect_success();
 }
 
-int test_range_tls_13_10()
+static int test_range_tls_13_10()
 {
   otlp::OtlpHttpExporterOptions opts;
 
@@ -1783,7 +1785,7 @@ int test_range_tls_13_10()
   return expect_connection_failed();
 }
 
-int test_range_tls_13_11()
+static int test_range_tls_13_11()
 {
   otlp::OtlpHttpExporterOptions opts;
 
@@ -1815,7 +1817,7 @@ int test_range_tls_13_11()
   return expect_connection_failed();
 }
 
-int test_range_tls_13_12()
+static int test_range_tls_13_12()
 {
   otlp::OtlpHttpExporterOptions opts;
 
@@ -1847,7 +1849,7 @@ int test_range_tls_13_12()
   return expect_connection_failed();
 }
 
-int test_gzip_compression()
+static int test_gzip_compression()
 {
   otlp::OtlpHttpExporterOptions opts;
 
diff --git a/sdk/src/common/env_variables.cc b/sdk/src/common/env_variables.cc
index b72933a802..296cef6306 100644
--- a/sdk/src/common/env_variables.cc
+++ b/sdk/src/common/env_variables.cc
@@ -26,7 +26,7 @@ namespace sdk
 namespace common
 {
 
-bool GetRawEnvironmentVariable(const char *env_var_name, std::string &value)
+static bool GetRawEnvironmentVariable(const char *env_var_name, std::string &value)
 {
 #if !defined(NO_GETENV)
   const char *endpoint_from_env = nullptr;
diff --git a/sdk/src/metrics/aggregation/base2_exponential_histogram_aggregation.cc b/sdk/src/metrics/aggregation/base2_exponential_histogram_aggregation.cc
index aaac9a0d0e..70d915bb04 100644
--- a/sdk/src/metrics/aggregation/base2_exponential_histogram_aggregation.cc
+++ b/sdk/src/metrics/aggregation/base2_exponential_histogram_aggregation.cc
@@ -218,9 +218,9 @@ void Base2ExponentialHistogramAggregation::Downscale(uint32_t by) noexcept
 
 // Merge A and B into a new circular buffer C.
 // Caller must ensure that A and B are used as buckets at the same scale.
-AdaptingCircularBufferCounter MergeBuckets(size_t max_buckets,
-                                           const AdaptingCircularBufferCounter &A,
-                                           const AdaptingCircularBufferCounter &B)
+static AdaptingCircularBufferCounter MergeBuckets(size_t max_buckets,
+                                                  const AdaptingCircularBufferCounter &A,
+                                                  const AdaptingCircularBufferCounter &B)
 {
   AdaptingCircularBufferCounter C = AdaptingCircularBufferCounter(max_buckets);
   C.Clear();
diff --git a/sdk/src/metrics/export/periodic_exporting_metric_reader_options.cc b/sdk/src/metrics/export/periodic_exporting_metric_reader_options.cc
index 94dbed48f8..4b9f86d2a9 100644
--- a/sdk/src/metrics/export/periodic_exporting_metric_reader_options.cc
+++ b/sdk/src/metrics/export/periodic_exporting_metric_reader_options.cc
@@ -14,8 +14,8 @@ namespace sdk
 namespace metrics
 {
 
-std::chrono::milliseconds GetEnvDuration(nostd::string_view env_var_name,
-                                         std::chrono::milliseconds default_value)
+static std::chrono::milliseconds GetEnvDuration(nostd::string_view env_var_name,
+                                                std::chrono::milliseconds default_value)
 {
   std::chrono::system_clock::duration duration;
   if (common::GetDurationEnvironmentVariable(env_var_name.data(), duration))
diff --git a/sdk/test/common/circular_buffer_test.cc b/sdk/test/common/circular_buffer_test.cc
index 64075d5a6e..6dc1b627cc 100644
--- a/sdk/test/common/circular_buffer_test.cc
+++ b/sdk/test/common/circular_buffer_test.cc
@@ -63,9 +63,9 @@ static void RunNumberProducers(CircularBuffer<uint32_t> &buffer,
   }
 }
 
-void RunNumberConsumer(CircularBuffer<uint32_t> &buffer,
-                       std::atomic<bool> &exit,
-                       std::vector<uint32_t> &numbers)
+static void RunNumberConsumer(CircularBuffer<uint32_t> &buffer,
+                              std::atomic<bool> &exit,
+                              std::vector<uint32_t> &numbers)
 {
   while (true)
   {
diff --git a/sdk/test/common/random_test.cc b/sdk/test/common/random_test.cc
index 96cf24dd5c..e5711ef1a1 100644
--- a/sdk/test/common/random_test.cc
+++ b/sdk/test/common/random_test.cc
@@ -42,7 +42,7 @@ TEST(RandomTest, GenerateRandomBuffer)
   }
 }
 
-void doSomethingOnce(std::atomic_uint *count)
+static void doSomethingOnce(std::atomic_uint *count)
 {
   static std::atomic_flag flag;
   if (!flag.test_and_set())
diff --git a/sdk/test/metrics/instrument_descriptor_test.cc b/sdk/test/metrics/instrument_descriptor_test.cc
index f17189355c..6e689a2db0 100644
--- a/sdk/test/metrics/instrument_descriptor_test.cc
+++ b/sdk/test/metrics/instrument_descriptor_test.cc
@@ -8,7 +8,7 @@
 
 using namespace opentelemetry::sdk::metrics;
 
-InstrumentDescriptor CreateInstrumentDescriptor(
+static InstrumentDescriptor CreateInstrumentDescriptor(
     const std::string &name        = "counter",
     const std::string &description = "description",
     const std::string &unit        = "unit",
diff --git a/sdk/test/metrics/sync_instruments_test.cc b/sdk/test/metrics/sync_instruments_test.cc
index 0cff06a9ca..263441d38c 100644
--- a/sdk/test/metrics/sync_instruments_test.cc
+++ b/sdk/test/metrics/sync_instruments_test.cc
@@ -21,7 +21,7 @@ using namespace opentelemetry;
 using namespace opentelemetry::sdk::instrumentationscope;
 using namespace opentelemetry::sdk::metrics;
 
-auto instrumentation_scope = InstrumentationScope::Create("opentelemetry-cpp", "0.1.0");
+static auto instrumentation_scope = InstrumentationScope::Create("opentelemetry-cpp", "0.1.0");
 
 using M = std::map<std::string, std::string>;