gcc-macros

#!/bin/sh
# gcc-macros --- display all predefined macros in gcc
# Author: Noah Friedman <friedman@splode.com>
# Public domain

# $Id: gcc-macros,v 1.1 2005/10/13 03:18:47 friedman Exp $

# Commentary:

# By default this will print all the predefined macros for a vanilla C file.
# To override the language, use -x{c++,assembler} etc.
# To change the language standards conformance,
# use -std={c89,c99,gnu89,gnu99,c++98,gnu++98} etc.

# Code:

case ${LANG+is_set} in
  is_set ) LANG=C ;;
esac

xlang=c

# See if we should change the default lang used here because of a -std arg.
# A few other knobs and frobs here also.
for arg in ${1+"$@"} ; do
  case $arg in
    -std=*++* | -x[cg]++ | [cg]++ ) xlang=c++ ; shift ;;
    -prog=* )
      shift
      arg=`echo "$arg" | sed -e 's/^[^=]*=//'`
      ccprog=`${CC-gcc} -print-prog-name=$arg` ;;
    -noargs | -noxargs ) shift; noxargs=t ;;
  esac
done

# osx10.2/darwin6.8 note: `gcc -dM' will not display any macros because it
# calls cpp-precomp, which doesn't print the defines it knows about.
# However when invoking for c++ it does call cpp0.
case $xlang in
  c ) case `uname -s`:`uname -r` in
        Darwin:6.[0-8] ) CC=${CC-cpp} ;;
      esac ;;
esac

# If -x[foo] is passed on the command line, it will override the -x arg here.
# Some versions of cpp (gcc 3.1?) will not do the right thing if -x and [foo]
# are separated by a space.
case $noxargs in
  t ) set fnord -dM ${1+"$@"} ;;
  * ) set fnord -dM -E -x$xlang ${1+"$@"} ;;
esac
shift

echo ${ccprog-${CC-gcc}} ${1+"$@"}
${ccprog-${CC-gcc}} ${1+"$@"} /dev/null | sort

# eof