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/⟩.