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.1‐2008, 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.1‐2008,   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.1‐2008, 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, 2013 Edition, Standard for Information Technology  --  Portable  Operating  System
       Interface  (POSIX),  The Open Group Base Specifications Issue 7, Copyright (C) 2013 by the
       Institute of Electrical and Electronics Engineers, Inc  and  The  Open  Group.   (This  is
       POSIX.1-2008  with  the  2013  Technical  Corrigendum  1  applied.)  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.unix.org/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 .