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⟩,       or       via       Savannah:
       ⟨https://savannah.gnu.org/support/?group=autoconf⟩.

COPYRIGHT

       Copyright  © 2023 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 Autoconf is maintained as a Texinfo manual.  To read the manual
       locally, use the command

              info autoconf

       You     can     also     consult     the     Web     version     of    the    manual    at
       ⟨https://gnu.org/software/autoconf/manual/⟩.