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.
NAMEcflow - generate a C-language flowgraph (DEVELOPMENT)
SYNOPSIScflow [-r][-d num][-D name[=def]] ... [-i incl][-I dir] ...
[-U dir] ... file ...
The cflow utility shall analyze a collection of object files or assem‐
bler, C-language, lex, or yacc source files, and attempt to build a
graph, written to standard output, charting the external references.
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:
Indicate the depth at which the flowgraph is cut off. The appli‐
cation 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.
Increase the number of included symbols. The incl option-argu‐
ment is one of the following characters:
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
-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.
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
Files suffixed by .s (conventionally assembler source) may have more
limited information extracted from them.
The input files shall be object files or assembler, C-language, lex, or
yacc source files.
The following environment variables shall affect the execution of
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 Vari‐
ables 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.
Determine the locale for the ordering of the output when the -r
option is used.
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).
Determine the locale that should be used to affect the format
and contents of diagnostic messages written to standard error.
Determine the location of message catalogs for the processing of
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 inclu‐
sion option. For information extracted from C-language source, the def‐
inition 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 defi‐
nition can be found. For undefined references, only "<>" shall be writ‐
The standard error shall be used only for diagnostic messages.
The following exit values shall be returned:
0 Successful completion.
>0 An error occurred.
CONSEQUENCES OF ERRORS
The following sections are informative.
Files produced by lex and yacc cause the reordering of line number dec‐
larations, and this can confuse cflow. To obtain proper results, the
input of yacc or lex must be directed to cflow.
Given the following in file.c:
i = h();
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: <>
c99, lex, yacc
Portions of this text are reprinted and reproduced in electronic form
from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology
-- Portable Operating System Interface (POSIX), The Open Group Base
Specifications Issue 6, Copyright (C) 2001-2003 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 .
IEEE/The Open Group 2003 CFLOW(1P)