Fixed warning "unused variable" with GCC 4.4 (issue bblanchon#912)

bblanchon · bblanchon · commit f342dee2b45f · 2019-02-28T15:34:21.000+01:00
diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -4,6 +4,7 @@ ArduinoJson: change log
 HEAD
 ----
 
+* Fixed warning "unused variable" with GCC 4.4 (issue #912)
 * Added a clear error message for `StaticJsonBuffer` and `DynamicJsonBuffer`
 
 v6.9.0 (2019-02-26)
diff --git a/src/ArduinoJson/Numbers/FloatTraits.hpp b/src/ArduinoJson/Numbers/FloatTraits.hpp
@@ -98,12 +98,8 @@ struct FloatTraits<T, 8 /*64bits*/> {
   // we use this function to workaround platforms with single precision literals
   // (for example, when -fsingle-precision-constant is passed to GCC)
   static T forge(uint32_t msb, uint32_t lsb) {
-    union {
-      uint64_t integerBits;
-      T floatBits;
-    };
-    integerBits = (uint64_t(msb) << 32) | lsb;
-    return floatBits;
+    uint64_t bits = (uint64_t(msb) << 32) | lsb;
+    return *reinterpret_cast<T*>(&bits);
   }
 };
 
@@ -150,12 +146,7 @@ struct FloatTraits<T, 4 /*32bits*/> {
   }
 
   static T forge(uint32_t bits) {
-    union {
-      uint32_t integerBits;
-      T floatBits;
-    };
-    integerBits = bits;
-    return floatBits;
+    return *reinterpret_cast<T*>(&bits);
   }
 
   static T nan() {
