In class diagrams of C/C++ elements, a manifestation relationship exists between a class and a class definition when the class definition is contained in a C/C++ header file.
In C/C++, class definitions outline the characteristics of the class design. The class definitions are stored in C/C++ header files which have a file name extension of *.h or *.hpp. A header file might contain more than one class definition.
As the figure in the following table illustrates, a manifestation relationship connector appears as a dashed line with an unfilled arrowhead. The connector points from the header file, which is the class definition, to the class, which is the manifestation of the class.
C/C++ header file | C/C++ class diagram |