diff --git a/src/HttpServer.cc b/src/HttpServer.cc
index 3e662e93..c1022c38 100644
--- a/src/HttpServer.cc
+++ b/src/HttpServer.cc
@@ -1725,7 +1725,7 @@ int HttpServer::run()
     EC_KEY_free(ecdh);
 #endif // OPENSSL_VERSION_NUBMER < 0x10002000L
 
-#endif /* OPENSSL_NO_EC */
+#endif // OPENSSL_NO_EC
 
     if(SSL_CTX_use_PrivateKey_file(ssl_ctx,
                                    config_->private_key_file.c_str(),
diff --git a/src/comp_helper.h b/src/comp_helper.h
index d5db2e27..4afb1e82 100644
--- a/src/comp_helper.h
+++ b/src/comp_helper.h
@@ -27,7 +27,7 @@
 
 #ifdef HAVE_CONFIG_H
 #  include <config.h>
-#endif /* HAVE_CONFIG_H */
+#endif // HAVE_CONFIG_H
 
 #include <jansson.h>
 
@@ -44,4 +44,4 @@ void output_json_header(void);
 
 void output_json_footer(void);
 
-#endif /* NGHTTP2_COMP_HELPER_H */
+#endif // NGHTTP2_COMP_HELPER_H
diff --git a/src/deflatehd.cc b/src/deflatehd.cc
index 4f036d18..5081910a 100644
--- a/src/deflatehd.cc
+++ b/src/deflatehd.cc
@@ -24,7 +24,7 @@
  */
 #ifdef HAVE_CONFIG_H
 #  include <config.h>
-#endif /* HAVE_CONFIG_H */
+#endif // HAVE_CONFIG_H
 
 #include <unistd.h>
 #include <getopt.h>
@@ -108,7 +108,7 @@ static void output_to_json(nghttp2_hd_deflater *deflater,
   }
   json_object_set_new(obj, "headers", dump_headers(nva.data(), nva.size()));
   if(seq == 0) {
-    /* We only change the header table size only once at the beginning */
+    // We only change the header table size only once at the beginning
     json_object_set_new(obj, "header_table_size",
                         json_integer(config.table_size));
   }
@@ -293,7 +293,7 @@ static int perform_from_http1text(void)
       for(val_end = val; *val_end && (*val_end != '\r' && *val_end != '\n');
           ++val_end);
       *val_end = '\0';
-      /* printf("[%s] : [%s]\n", line, val); */
+
       nv->namelen = strlen(line);
       nv->valuelen = strlen(val);
       nv->name = (uint8_t*)strdup(line);
@@ -423,11 +423,11 @@ int main(int argc, char **argv)
       print_help();
       exit(EXIT_SUCCESS);
     case 't':
-      /* --http1text */
+      // --http1text
       config.http1text = 1;
       break;
     case 's':
-      /* --table-size */
+      // --table-size
       errno = 0;
       config.table_size = strtoul(optarg, &end, 10);
       if(errno == ERANGE || *end != '\0') {
@@ -436,7 +436,7 @@ int main(int argc, char **argv)
       }
       break;
     case 'S':
-      /* --deflate-table-size */
+      // --deflate-table-size
       errno = 0;
       config.deflate_table_size = strtoul(optarg, &end, 10);
       if(errno == ERANGE || *end != '\0') {
@@ -445,11 +445,11 @@ int main(int argc, char **argv)
       }
       break;
     case 'd':
-      /* --dump-header-table */
+      // --dump-header-table
       config.dump_header_table = 1;
       break;
     case 'c':
-      /* --no-refset */
+      // --no-refset
       config.no_refset = 1;
       break;
     case '?':
diff --git a/src/h2load.cc b/src/h2load.cc
index 73627cad..a2f96e5b 100644
--- a/src/h2load.cc
+++ b/src/h2load.cc
@@ -671,7 +671,7 @@ int main(int argc, char **argv)
 		  "no threads created." << std::endl;
 #else
       config.nthreads = strtoul(optarg, nullptr, 10);
-#endif /* NOTHREADS */
+#endif // NOTHREADS
       break;
     case 'm':
       if(util::strieq("auto", optarg)) {
@@ -783,7 +783,7 @@ int main(int argc, char **argv)
 
 #ifndef NOTHREADS
   ssl::LibsslGlobalLock();
-#endif /* NOTHREADS */
+#endif // NOTHREADS
 
   auto ssl_ctx = SSL_CTX_new(SSLv23_client_method());
   if(!ssl_ctx) {
diff --git a/src/inflatehd.cc b/src/inflatehd.cc
index 1d36be6e..6f48ae00 100644
--- a/src/inflatehd.cc
+++ b/src/inflatehd.cc
@@ -24,7 +24,7 @@
  */
 #ifdef HAVE_CONFIG_H
 #  include <config.h>
-#endif /* HAVE_CONFIG_H */
+#endif // HAVE_CONFIG_H
 
 #include <unistd.h>
 #include <getopt.h>
@@ -271,7 +271,7 @@ int main(int argc, char **argv)
       print_help();
       exit(EXIT_SUCCESS);
     case 'd':
-      /* --dump-header-table */
+      // --dump-header-table
       config.dump_header_table = 1;
       break;
     case '?':
diff --git a/src/nghttp.cc b/src/nghttp.cc
index 2a467e13..0e17d197 100644
--- a/src/nghttp.cc
+++ b/src/nghttp.cc
@@ -991,14 +991,14 @@ int htp_msg_completecb(http_parser *htp)
 
 namespace {
 http_parser_settings htp_hooks = {
-  htp_msg_begincb, /*http_cb      on_message_begin;*/
-  nullptr, /*http_data_cb on_url;*/
-  htp_status_completecb, /*http_cb on_status_complete */
-  nullptr, /*http_data_cb on_header_field;*/
-  nullptr, /*http_data_cb on_header_value;*/
-  nullptr, /*http_cb      on_headers_complete;*/
-  nullptr, /*http_data_cb on_body;*/
-  htp_msg_completecb /*http_cb      on_message_complete;*/
+  htp_msg_begincb, // http_cb      on_message_begin;
+  nullptr, // http_data_cb on_url;
+  htp_status_completecb, // http_cb on_status_complete;
+  nullptr, // http_data_cb on_header_field;
+  nullptr, // http_data_cb on_header_value;
+  nullptr, // http_cb      on_headers_complete;
+  nullptr, // http_data_cb on_body;
+  htp_msg_completecb // http_cb      on_message_complete;
 };
 } // namespace
 
diff --git a/src/nghttpd.cc b/src/nghttpd.cc
index 9e471c28..b6ef4ff2 100644
--- a/src/nghttpd.cc
+++ b/src/nghttpd.cc
@@ -195,7 +195,7 @@ int main(int argc, char **argv)
         std::cerr << "-n: Bad option value: " << optarg << std::endl;
         exit(EXIT_FAILURE);
       }
-#endif /* NOTHREADS */
+#endif // NOTHREADS
       break;
     case 'h':
       print_help(std::cout);
@@ -278,7 +278,7 @@ int main(int argc, char **argv)
   SSL_library_init();
 #ifndef NOTHREADS
   ssl::LibsslGlobalLock();
-#endif /* NOTHREADS */
+#endif // NOTHREADS
 
   reset_timer();
 
diff --git a/src/shrpx-unittest.cc b/src/shrpx-unittest.cc
index 0a6c16fc..6015ad4b 100644
--- a/src/shrpx-unittest.cc
+++ b/src/shrpx-unittest.cc
@@ -27,7 +27,7 @@
 #include <CUnit/Basic.h>
 #include <openssl/ssl.h>
 #include <openssl/err.h>
-/* include test cases' include files here */
+// include test cases' include files here
 #include "shrpx_ssl_test.h"
 #include "shrpx_downstream_test.h"
 #include "shrpx_config_test.h"
@@ -55,18 +55,18 @@ int main(int argc, char* argv[])
    SSL_load_error_strings();
    SSL_library_init();
 
-   /* initialize the CUnit test registry */
+   // initialize the CUnit test registry
    if (CUE_SUCCESS != CU_initialize_registry())
       return CU_get_error();
 
-   /* add a suite to the registry */
+   // add a suite to the registry
    pSuite = CU_add_suite("shrpx_TestSuite", init_suite1, clean_suite1);
    if (NULL == pSuite) {
       CU_cleanup_registry();
       return CU_get_error();
    }
 
-   /* add the tests to the suite */
+   // add the tests to the suite
    if(!CU_add_test(pSuite, "ssl_create_lookup_tree",
                    shrpx::test_shrpx_ssl_create_lookup_tree) ||
       !CU_add_test(pSuite, "ssl_cert_lookup_tree_add_cert_from_file",
@@ -124,7 +124,7 @@ int main(int argc, char* argv[])
      return CU_get_error();
    }
 
-   /* Run all tests using the CUnit Basic interface */
+   // Run all tests using the CUnit Basic interface
    CU_basic_set_mode(CU_BRM_VERBOSE);
    CU_basic_run_tests();
    num_tests_failed = CU_get_number_of_tests_failed();
diff --git a/src/shrpx.cc b/src/shrpx.cc
index b9a910f0..6d752043 100644
--- a/src/shrpx.cc
+++ b/src/shrpx.cc
@@ -913,7 +913,7 @@ int main(int argc, char **argv)
 	  LOG(WARNING) << "Threading disabled at build time, no threads created.";
 #else
       cmdcfgs.emplace_back(SHRPX_OPT_WORKERS, optarg);
-#endif /* NOTHREADS */
+#endif // NOTHREADS
       break;
     case 'o':
       cmdcfgs.emplace_back(SHRPX_OPT_FRONTEND_FRAME_DEBUG, "yes");
@@ -1161,7 +1161,7 @@ int main(int argc, char **argv)
   SSL_library_init();
 #ifndef NOTHREADS
   nghttp2::ssl::LibsslGlobalLock();
-#endif /* NOTHREADS */
+#endif // NOTHREADS
 
   if(conf_exists(get_config()->conf_path)) {
     if(load_config(get_config()->conf_path) == -1) {
diff --git a/src/shrpx_config_test.h b/src/shrpx_config_test.h
index 50f2b347..6b915766 100644
--- a/src/shrpx_config_test.h
+++ b/src/shrpx_config_test.h
@@ -32,4 +32,4 @@ void test_shrpx_config_parse_header(void);
 
 } // namespace shrpx
 
-#endif /* SHRPX_CONFIG_TEST_H */
+#endif // SHRPX_CONFIG_TEST_H
diff --git a/src/shrpx_http2_session.cc b/src/shrpx_http2_session.cc
index 0f52a7f0..1382839b 100644
--- a/src/shrpx_http2_session.cc
+++ b/src/shrpx_http2_session.cc
@@ -527,14 +527,14 @@ int htp_hdrs_completecb(http_parser *htp)
 
 namespace {
 http_parser_settings htp_hooks = {
-  nullptr, /*http_cb      on_message_begin;*/
-  nullptr, /*http_data_cb on_url;*/
-  nullptr, /*http_cb on_status_complete */
-  nullptr, /*http_data_cb on_header_field;*/
-  nullptr, /*http_data_cb on_header_value;*/
-  htp_hdrs_completecb, /*http_cb      on_headers_complete;*/
-  nullptr, /*http_data_cb on_body;*/
-  nullptr  /*http_cb      on_message_complete;*/
+  nullptr, // http_cb      on_message_begin;
+  nullptr, // http_data_cb on_url;
+  nullptr, // http_cb on_status_complete;
+  nullptr, // http_data_cb on_header_field;
+  nullptr, // http_data_cb on_header_value;
+  htp_hdrs_completecb, // http_cb      on_headers_complete;
+  nullptr, // http_data_cb on_body;
+  nullptr  // http_cb      on_message_complete;
 };
 } // namespace
 
diff --git a/src/shrpx_http_downstream_connection.cc b/src/shrpx_http_downstream_connection.cc
index 4a895bff..a343df69 100644
--- a/src/shrpx_http_downstream_connection.cc
+++ b/src/shrpx_http_downstream_connection.cc
@@ -488,14 +488,14 @@ int htp_msg_completecb(http_parser *htp)
 
 namespace {
 http_parser_settings htp_hooks = {
-  nullptr, /*http_cb      on_message_begin;*/
-  nullptr, /*http_data_cb on_url;*/
-  nullptr, /*http_cb on_status_complete */
-  htp_hdr_keycb, /*http_data_cb on_header_field;*/
-  htp_hdr_valcb, /*http_data_cb on_header_value;*/
-  htp_hdrs_completecb, /*http_cb      on_headers_complete;*/
-  htp_bodycb, /*http_data_cb on_body;*/
-  htp_msg_completecb /*http_cb      on_message_complete;*/
+  nullptr, // http_cb      on_message_begin;
+  nullptr, // http_data_cb on_url;
+  nullptr, // http_cb on_status_complete;
+  htp_hdr_keycb, // http_data_cb on_header_field;
+  htp_hdr_valcb, // http_data_cb on_header_value;
+  htp_hdrs_completecb, // http_cb      on_headers_complete;
+  htp_bodycb, // http_data_cb on_body;
+  htp_msg_completecb // http_cb      on_message_complete;
 };
 } // namespace
 
diff --git a/src/shrpx_https_upstream.cc b/src/shrpx_https_upstream.cc
index 6a00f3be..13c09cc5 100644
--- a/src/shrpx_https_upstream.cc
+++ b/src/shrpx_https_upstream.cc
@@ -246,14 +246,14 @@ int htp_msg_completecb(http_parser *htp)
 
 namespace {
 http_parser_settings htp_hooks = {
-  htp_msg_begin, /*http_cb      on_message_begin;*/
-  htp_uricb, /*http_data_cb on_url;*/
-  nullptr, /*http_cb on_status_complete */
-  htp_hdr_keycb, /*http_data_cb on_header_field;*/
-  htp_hdr_valcb, /*http_data_cb on_header_value;*/
-  htp_hdrs_completecb, /*http_cb      on_headers_complete;*/
-  htp_bodycb, /*http_data_cb on_body;*/
-  htp_msg_completecb /*http_cb      on_message_complete;*/
+  htp_msg_begin, // http_cb      on_message_begin;
+  htp_uricb, // http_data_cb on_url;
+  nullptr, // http_cb on_status_complete;
+  htp_hdr_keycb, // http_data_cb on_header_field;
+  htp_hdr_valcb, // http_data_cb on_header_value;
+  htp_hdrs_completecb, // http_cb      on_headers_complete;
+  htp_bodycb, // http_data_cb on_body;
+  htp_msg_completecb // http_cb      on_message_complete;
 };
 } // namespace
 
diff --git a/src/shrpx_ssl.cc b/src/shrpx_ssl.cc
index 7bc2723e..40b5e110 100644
--- a/src/shrpx_ssl.cc
+++ b/src/shrpx_ssl.cc
@@ -296,7 +296,7 @@ SSL_CTX* create_ssl_context(const char *private_key_file,
   EC_KEY_free(ecdh);
 #endif // OPENSSL_VERSION_NUBMER < 0x10002000L
 
-#endif /* OPENSSL_NO_EC */
+#endif // OPENSSL_NO_EC
 
   if(get_config()->dh_param_file) {
     // Read DH parameters from file
diff --git a/src/shrpx_ssl_test.h b/src/shrpx_ssl_test.h
index b0ac8ca6..fbb1fa62 100644
--- a/src/shrpx_ssl_test.h
+++ b/src/shrpx_ssl_test.h
@@ -32,4 +32,4 @@ void test_shrpx_ssl_cert_lookup_tree_add_cert_from_file(void);
 
 } // namespace shrpx
 
-#endif /* SHRPX_SSL_TEST_H */
+#endif // SHRPX_SSL_TEST_H