NAME

       ifnames - Extract CPP conditionals from a set of files

SYNOPSIS

       ifnames [OPTION]... [FILE]...

DESCRIPTION

       Scan all of the C source FILES (or the standard input, if none are given) and write to the
       standard output a sorted list of all the identifiers that appear in those files in  '#if',
       '#elif',  '#ifdef', or '#ifndef' directives.  Print each identifier on a line, followed by
       a space-separated list of the files in which that identifier occurs.

       -h, --help
              print this help, then exit

       -V, --version
              print version number, then exit

AUTHOR

       Written by David J. MacKenzie and Paul Eggert.

REPORTING BUGS

       Report bugs to <bug-autoconf@gnu.org>.
       GNU Autoconf home page: <https://www.gnu.org/software/autoconf/>.
       General help using GNU software: <https://www.gnu.org/gethelp/>.

COPYRIGHT

       Copyright © 2021 Free Software Foundation, Inc.  License GPLv3+/Autoconf: GNU GPL  version
       3 or later <https://gnu.org/licenses/gpl.html>, <https://gnu.org/licenses/exceptions.html>
       This  is free software: you are free to change and redistribute it.  There is NO WARRANTY,
       to the extent permitted by law.

SEE ALSO

       autoconf(1),  automake(1),  autoreconf(1),  autoupdate(1),   autoheader(1),   autoscan(1),
       config.guess(1), config.sub(1), ifnames(1), libtool(1).

       The  full  documentation  for  ifnames is maintained as a Texinfo manual.  If the info and
       ifnames programs are properly installed at your site, the command

              info ifnames

       should give you access to the complete manual.