Totalview® for HPC User Guide : PART II Debugging Tools and Tasks : Chapter 9 Examining and Editing Data and Program Elements : Changing a Variable’s Data Type : Viewing Unions
Viewing Unions
TotalView displays a union in the same way that it displays a structure. Even though the fields of a union are overlaid in storage, TotalView displays the fields on separate lines.
CLI: dprint variable
  
Figure 141 – Displaying a Union