cflow(1)cflow(1)NAMEcflow - generate C flowgraph
SYNOPSIScflow [-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 refer‐
ences. 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 collected 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 suit‐
able number of tabs indicating the level, then the name of the global
symbol followed by a colon and its definition. 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 defini‐
tion consists of an abstract type declaration (e.g., char ∗), and,
delimited 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 location 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 interpreted 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 function. 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 flow‐
graph is cut off. By default this number is very large.
Attempts to set the cutoff depth to a nonpositive integer will
be ignored.
SEE ALSOas(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 dec‐
larations, which can confuse cflow. To get proper results, feed cflow
the yacc or lex input.
March 1998 0a
