cflow(1p) — Linux manual page
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 (consult 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
POSIX.1‐2017, 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
decimal 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 POSIX.1‐2017, Section 8.2,
Internationalization Variables for the precedence of
internationalization 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
standard 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 position
per level. This is followed by the name of the global, a
<colon>, and its definition. Normally globals are only functions
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.
SEE ALSO
c99(1p), lex(1p), yacc(1p)
The Base Definitions volume of POSIX.1‐2017, Chapter 8,
Environment Variables, Section 12.2, Utility Syntax Guidelines
COPYRIGHT
Portions of this text are reprinted and reproduced in electronic
form from IEEE Std 1003.1-2017, Standard for Information
Technology -- Portable Operating System Interface (POSIX), The
Open Group Base Specifications Issue 7, 2018 Edition, Copyright
(C) 2018 by the Institute of Electrical and Electronics
Engineers, Inc and The Open Group. In the event of any
discrepancy between this version and the original IEEE and The
Open Group Standard, the original IEEE and The Open Group
Standard is the referee document. The original Standard can be
obtained online at http://www.opengroup.org/unix/online.html .
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