NAME
cflow - generate C flowgraph
SYNOPSIS
cflow [-r] [-ix] [-i_] [-dnum] files
DESCRIPTION
The cflow command analyzes a collection of C, yacc, lex,
assembler, and object files and builds a graph charting the
external function references. Files suffixed with .y, .l,
and .c are processed by yacc, lex, and the C compiler as
appropriate. The results of the preprocessed files, and
files suffixed with .i, are then run through the first pass
of lint. Files suffixed with .s are assembled. Assembled
files, and files suffixed with .o, have information
extracted from their symbol tables. The results are col-
lected and turned into a graph of external references that
is written on the standard output.
Each line of output begins with a reference number, followed
by a suitable number of tabs indicating the level, then the
name of the global symbol followed by a colon and its defin-
ition. Normally only function names that do not begin with
an underscore are listed (see the -i options below). For
information extracted from C source, the definition consists
of an abstract type declaration (e.g., char *), and, delim-
ited by angle brackets, the name of the source file and the
line number where the definition was found. Definitions
extracted from object files indicate the file name and loca-
tion counter under which the symbol appeared (e.g., text).
Leading underscores in C-style external names are deleted.
Once a definition of a name has been printed, subsequent
references to that name contain only the reference number of
the line where the definition may be found. For undefined
references, only <> is printed.
As an example, suppose the following code is in file.c:
int i;
main()
{
f();
g();
f();
}
f()
{
i = h();
}
The command
cflow -ix file.c
produces the output
1 main: int(), <file.c 4>
2 f: int(), <file.c 11>
3 h: <>
4 i: int, <file.c 1>
5 g: <>
When the nesting level becomes too deep, the output of cflow
can be piped to the pr command, using the -e option, to
compress the tab expansion to something less than every
eight spaces.
In addition to the -D, -I, and -U options, which are inter-
preted just as they are by cc, the following options are
interpreted by cflow:
-r Reverse the ``caller:callee'' relationship producing
an inverted listing showing the callers of each func-
tion. The listing is also sorted in lexicographical
order by callee.
-ix Include external and static data symbols. The default
is to include only functions in the flowgraph.
-i_ Include names that begin with an underscore. The
default is to exclude these functions (and data if
-ix is used).
-dnum The num decimal integer indicates the depth at which
the flowgraph is cut off. By default this number is
very large. Attempts to set the cutoff depth to a
nonpositive integer will be ignored.
SEE ALSO
as(1), cc(1) lex(1), lint(1), nm(1), pr(1), yacc(1)
DIAGNOSTICS
Complains about multiple definitions and only believes the
first.
NOTES
Files produced by lex and yacc cause the reordering of line
number declarations, which can confuse cflow. To get proper
results, feed cflow the yacc or lex input.