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CFLOW(1P) POSIX Programmer's Manual CFLOW(1P)

PROLOG
This manual page is part of the POSIX Programmer's Manual. The Linux implementation of this interface may differ (con-
sult the corresponding Linux manual page for details of Linux behavior), or the interface may not be implemented on
Linux.

NAME
cflow - generate a C-language flowgraph (DEVELOPMENT)

SYNOPSIS
cflow [-r][-d num][-D name[=def]] ... [-i incl][-I dir] ...
[-U dir] ... file ...

DESCRIPTION
The cflow utility shall analyze a collection of object files or assembler, C-language, lex, or yacc source files, and
attempt to build a graph, written to standard output, charting the external references.

OPTIONS
The cflow utility shall conform to the Base Definitions volume of IEEE Std 1003.1-2001, Section 12.2, Utility Syntax
Guidelines, except that the order of the -D, -I, and -U options (which are identical to their interpretation by c99) is
significant.

The following options shall be supported:

-d num
Indicate the depth at which the flowgraph is cut off. The application shall ensure that the argument num is a dec-
imal integer. By default this is a very large number (typically greater than 32000). Attempts to set the cut-off
depth to a non-positive integer shall be ignored.

-i incl
Increase the number of included symbols. The incl option-argument is one of the following characters:

x
Include external and static data symbols. The default shall be to include only functions in the flowgraph.

_
(Underscore) Include names that begin with an underscore. The default shall be to exclude these functions (and
data if -i x is used).

-r Reverse the caller:callee relationship, producing an inverted listing showing the callers of each function. The
listing shall also be sorted in lexicographical order by callee.

OPERANDS
The following operand is supported:

file The pathname of a file for which a graph is to be generated. Filenames suffixed by .l shall shall be taken to be
lex input, .y as yacc input, .c as c99 input, and .i as the output of c99 -E. Such files shall be processed as
appropriate, determined by their suffix.

Files suffixed by .s (conventionally assembler source) may have more limited information extracted from them.

STDIN
Not used.

INPUT FILES
The input files shall be object files or assembler, C-language, lex, or yacc source files.

ENVIRONMENT VARIABLES
The following environment variables shall affect the execution of cflow:

LANG Provide a default value for the internationalization variables that are unset or null. (See the Base Definitions
volume of IEEE Std 1003.1-2001, Section 8.2, Internationalization Variables for the precedence of international-
ization variables used to determine the values of locale categories.)

LC_ALL If set to a non-empty string value, override the values of all the other internationalization variables.

LC_COLLATE

Determine the locale for the ordering of the output when the -r option is used.

LC_CTYPE
Determine the locale for the interpretation of sequences of bytes of text data as characters (for example, single-
byte as opposed to multi-byte characters in arguments and input files).

LC_MESSAGES
Determine the locale that should be used to affect the format and contents of diagnostic messages written to stan-
dard error.

NLSPATH
Determine the location of message catalogs for the processing of LC_MESSAGES .

ASYNCHRONOUS EVENTS
Default.

STDOUT
The flowgraph written to standard output shall be formatted as follows:

"%d %s:%s\n", <reference number>, <global>, <definition>

Each line of output begins with a reference (that is, line) number, followed by indentation of at least one column posi-
tion per level. This is followed by the name of the global, a colon, and its definition. Normally globals are only func-
tions not defined as an external or beginning with an underscore; see the OPTIONS section for the -i inclusion option.
For information extracted from C-language source, the definition consists of an abstract type declaration (for example,
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 filename and location counter under which the symbol appeared (for
example, text).

Once a definition of a name has been written, subsequent references to that name contain only the reference number of the
line where the definition can be found. For undefined references, only "<>" shall be written.

STDERR
The standard error shall be used only for diagnostic messages.

OUTPUT FILES
None.

EXTENDED DESCRIPTION
None.

EXIT STATUS
The following exit values shall be returned:

0 Successful completion.

>0 An error occurred.

CONSEQUENCES OF ERRORS
Default.

The following sections are informative.

APPLICATION USAGE
Files produced by lex and yacc cause the reordering of line number declarations, and this can confuse cflow. To obtain
proper results, the input of yacc or lex must be directed to cflow.

EXAMPLES
Given the following in file.c:

int i;
int f();
int g();
int h();
int
main()
{
f();
g();
f();
}
int
f()
{
i = h();
}

The command:

cflow -i x file.c

produces the output:

1 main: int(), <file.c 6>
2 f: int(), <file.c 13>
3 h: <>
4 i: int, <file.c 1>
5 g: <>

RATIONALE
None.

FUTURE DIRECTIONS
None.