diff --git a/.circleci/config.yml b/.circleci/config.yml
index 6bb4af0c1f..23dce4d88b 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -91,6 +91,21 @@ jobs:
       - run:
           name: Running phpcs
           command: composer lint -- --report=junit | tee test-results/phpcs/results.xml
+      - run:
+          name: Install clang-format 6.0
+          command: sudo apt -y install clang-format-6.0/testing
+      - run:
+          name: Run clang-format
+          command: |
+            find ./ -iname *.h -o -iname *.c | while read fname; do
+              changes=$(clang-format-6.0 -output-replacements-xml $fname | grep -c "<replacement " || true)
+              if [ $changes != 0 ]
+              then
+                clang-format-6.0 -output-replacements-xml $fname
+                echo "$fname did not pass clang-format, consider running: find ./ -iname *.h -o -iname *.c | xargs clang-format -i"
+                exit 1
+              fi
+            done
       - <<: *STEP_STORE_TEST_RESULTS
       - <<: *STEP_STORE_ARTIFACTS
 
@@ -153,17 +168,20 @@ jobs:
   "build 7.0":
     <<: *BASE_BUILD
     docker: [ image: 'circleci/php:7.0' ]
+
   "build 7.1":
     <<: *BASE_BUILD
     docker: [ image: 'circleci/php:7.1' ]
+
   "build 7.2":
     <<: *BASE_BUILD
     docker: [ image: 'circleci/php:7.2' ]
 
-
   "php-5.6":
     <<: *JOB_PHP_DEFAULTS
-    docker: [ image: 'circleci/php:5.6', *IMAGE_DOCKER_DD_AGENT ]
+    docker:
+      - image: 'circleci/php:5.6'
+      - <<: *IMAGE_DOCKER_DD_AGENT
 
   "php-7.0":
     <<: *JOB_PHP_DEFAULTS
diff --git a/config.m4 b/config.m4
index a3b8d720af..43d42efb08 100644
--- a/config.m4
+++ b/config.m4
@@ -1,4 +1,4 @@
-PHP_ARG_ENABLE(ddtrace, whether to enable Datadog tracing support,[  --enable-ddtrace   Enable Datadog traing support])
+PHP_ARG_ENABLE(ddtrace, whether to enable Datadog tracing support,[  --enable-ddtrace   Enable Datadog training support])
 
 PHP_ARG_WITH(ddtrace-sanitize, whether to enable AddressSanitizer for ddtrace,[  --with-ddtrace-sanitize Build Datadog tracing with AddressSanitizer support], no, no)
 
diff --git a/src/ext/ddtrace.c b/src/ext/ddtrace.c
index b1cd668ff4..e46035c29c 100644
--- a/src/ext/ddtrace.c
+++ b/src/ext/ddtrace.c
@@ -15,11 +15,19 @@
 
 #include "debug.h"
 
-
 #define UNUSED_1(x) (void)(x)
-#define UNUSED_2(x, y) do { UNUSED_1(x); UNUSED_1(y); } while (0)
-#define UNUSED_3(x, y, z) do { UNUSED_1(x); UNUSED_1(y); UNUSED_1(z); } while (0)
-#define _GET_UNUSED_MACRO_OF_ARITY(_1,_2,_3, ARITY,...) UNUSED_ ## ARITY
+#define UNUSED_2(x, y) \
+    do {               \
+        UNUSED_1(x);   \
+        UNUSED_1(y);   \
+    } while (0)
+#define UNUSED_3(x, y, z) \
+    do {                  \
+        UNUSED_1(x);      \
+        UNUSED_1(y);      \
+        UNUSED_1(z);      \
+    } while (0)
+#define _GET_UNUSED_MACRO_OF_ARITY(_1, _2, _3, ARITY, ...) UNUSED_##ARITY
 #define UNUSED(...) _GET_UNUSED_MACRO_OF_ARITY(__VA_ARGS__, 3, 2, 1)(__VA_ARGS__)
 
 #if PHP_VERSION_ID < 70000
@@ -85,7 +93,6 @@ static PHP_RINIT_FUNCTION(ddtrace) {
         return SUCCESS;
     }
 
-
     zend_hash_init(&DDTRACE_G(class_lookup), 8, NULL, (dtor_func_t)table_dtor, 0);
     zend_hash_init(&DDTRACE_G(function_lookup), 8, NULL, (dtor_func_t)ddtrace_class_lookup_free, 0);
 
diff --git a/src/ext/dispatch_setup.c b/src/ext/dispatch_setup.c
index c4caf6da58..9c0be16e5e 100644
--- a/src/ext/dispatch_setup.c
+++ b/src/ext/dispatch_setup.c
@@ -29,22 +29,22 @@ static void php_execute(zend_execute_data *execute_data TSRMLS_DC) {
 #endif
 
 void ddtrace_dispatch_init() {
-    /**
-     * Replacing zend_execute_ex with anything other than original
-     * changes some of the bevavior in PHP compilation and execution
-     *
-     * e.g. it changes compilation of function calls to produce ZEND_DO_FCALL
-     * opcode instead of ZEND_DO_UCALL for user defined functions
-     *
-     * While this extension could be developed by using zend_execute_ex to hook
-     * into every execution. However hooking into opcode processing has the
-     * advantage of not hooking into some executable things like generators which
-     * gives a slight performance advantage.
-     */
-    #if PHP_VERSION_ID >= 70000
+/**
+ * Replacing zend_execute_ex with anything other than original
+ * changes some of the bevavior in PHP compilation and execution
+ *
+ * e.g. it changes compilation of function calls to produce ZEND_DO_FCALL
+ * opcode instead of ZEND_DO_UCALL for user defined functions
+ *
+ * While this extension could be developed by using zend_execute_ex to hook
+ * into every execution. However hooking into opcode processing has the
+ * advantage of not hooking into some executable things like generators which
+ * gives a slight performance advantage.
+ */
+#if PHP_VERSION_ID >= 70000
     ddtrace_original_execute_ex = zend_execute_ex;
     zend_execute_ex = php_execute;
-    #endif
+#endif
 
     ddtrace_old_fcall_handler = zend_get_user_opcode_handler(ZEND_DO_FCALL);
     zend_set_user_opcode_handler(ZEND_DO_FCALL, ddtrace_wrap_fcall);