diff --git a/library/x509.c b/library/x509.c
index 38eb2e6..d61ef4a 100644
--- a/library/x509.c
+++ b/library/x509.c
@@ -53,13 +53,17 @@
 #include <time.h>
 #endif
 
-#define CHECK(code) if ((ret = (code)) != 0) { return ret; }
+#define CHECK(code)                                     \
+    do {                                                \
+        if ((ret = (code)) != 0) {                      \
+            return ret;                                 \
+        }                                               \
+    } while (0)
+
 #define CHECK_RANGE(min, max, val)                      \
-    do                                                  \
-    {                                                   \
-        if ((val) < (min) || (val) > (max))    \
-        {                                               \
-            return ret;                              \
+    do {                                                \
+        if ((val) < (min) || (val) > (max)) {           \
+            return ret;                                 \
         }                                               \
     } while (0)