When viewing a c or c++ source file you can view the call hierarchy of a function or method by issuing the command :CCallHierarchy. This will open a temporary buffer with an inversed tree view of the hierarchy of callers of the requested function or method.
fun2(int) fun1(int) main() fun3(int) fun3(int)
While you are in the hierarchy tree buffer, you can jump to the call under the cursor using one of the following key bindings:
:CCallHierarchy can also be used to view the callees for a function or
method by invoking the command with a