cflow [options] filesProduce an outline (or flowchart) of external function calls for the C, lex, yacc, assembler, or object files. cflow also accepts the cc options -D, -I, and -U.
-dnStop outlining when nesting level n is reached.
-i_Include functions whose names begin with _.
-ixInclude external and static data symbols.
-rInvert the listing; show the callers of each function and sort in lexicographical order by callee.