Fixes Trac #12183 (GCC 6.1 thinks boost::container::string violates strict aliasing)

2016-05-16 16:59:25 +02:00
parent 132e57a348
commit b888d2ae47
2 changed files with 8 additions and 2 deletions
@@ -230,7 +230,13 @@ class basic_string_base

   protected:
   bool is_short() const
-   {  return static_cast<bool>(this->members_.m_repr.s.h.is_short != 0);  }
+   {
+      //Access and copy (to avoid UB) the first byte of the union to know if the
+      //active representation is short or long
+      short_header hdr;
+      *(unsigned char*)&hdr = *(unsigned char*)&this->members_.m_repr;
+      return hdr.is_short != 0;
+   }

   void is_short(bool yes)
   {