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



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

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 xx 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, lex, yacc

       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 .

       Any typographical or formatting errors that appear in this page are
       most likely to have been introduced during the conversion of the source
       files to man page format. To report such errors, see
       https://www.kernel.org/doc/man-pages/reporting_bugs.html .



IEEE/The Open Group                  2017                             CFLOW(1)
