Method is_alloced

sql/sql_string.h:465–465

    return thread_specific;
  }
  bool is_alloced() const { return alloced; }
  inline uint32 alloced_length() const { return Alloced_length;}
  inline uint32 extra_allocation() const { return extra_alloc;}
  inline void extra_allocation(size_t len) { extra_alloc= (uint32)len; }