GNU cflow analyzes a collection of C source files and prints a graph,
charting control flow within the program.
GNU cflow is able to produce both direct and inverted flowgraphs for
C sources. Optionally a cross-reference listing can be generated.
Two output formats are implemented: POSIX and GNU (extended).
Input files can optionally be preprocessed before analyzing.
The package also provides Emacs major mode for examining the produced
flowcharts in Emacs.