?RCS: $Id: cppstdin.U 1 2006-08-24 12:32:52Z rmanfredi $
?RCS:
?RCS: Copyright (c) 1991-1997, 2004-2006, Raphael Manfredi
?RCS: 
?RCS: You may redistribute only under the terms of the Artistic Licence,
?RCS: as specified in the README file that comes with the distribution.
?RCS: You may reuse parts of this distribution only within the terms of
?RCS: that same Artistic Licence; a copy of which may be found at the root
?RCS: of the source tree for dist 4.0.
?RCS:
?RCS: $Log: cppstdin.U,v $
?RCS: Revision 3.0.1.4  1994/10/29  16:08:34  ram
?RCS: patch36: added ?F: line for metalint file checking
?RCS:
?RCS: Revision 3.0.1.3  1994/01/24  14:05:38  ram
?RCS: patch16: comment for CPPLAST was missing
?RCS:
?RCS: Revision 3.0.1.2  1993/12/15  08:18:58  ram
?RCS: patch15: new variables cpprun and cpplast, guaranteed wrapper-free
?RCS: patch15: cppstdin now tries to use cc, even at the cost of a wrapper
?RCS:
?RCS: Revision 3.0.1.1  1993/08/25  14:00:53  ram
?RCS: patch6: remove wrapper when not actually used
?RCS:
?RCS: Revision 3.0  1993/08/18  12:05:38  ram
?RCS: Baseline for dist 3.0 netwide release.
?RCS:
?MAKE:cppstdin cppminus cpprun cpplast: contains test Myread Oldconfig Loc \
	cpp +cc rm hint osname gccversion startsh eunicefix
?MAKE:	-pick add $@ %<
?S:cppstdin:
?S:	This variable contains the command which will invoke the C
?S:	preprocessor on standard input and put the output to stdout.
?S:	It is primarily used by other Configure units that ask about
?S:	preprocessor symbols.
?S:.
?S:cppminus:
?S:	This variable contains the second part of the string which will invoke
?S:	the C preprocessor on the standard input and produce to standard
?S:	output.  This variable will have the value "-" if cppstdin needs
?S:	a minus to specify standard input, otherwise the value is "".
?S:.
?S:cpprun:
?S:	This variable contains the command which will invoke a C preprocessor
?S:	on standard input and put the output to stdout. It is guaranteed not
?S:	to be a wrapper and may be a null string if no preprocessor can be
?S:	made directly available. This preprocessor might be different from the
?S:	one used by the C compiler. Don't forget to append cpplast after the
?S:	preprocessor options.
?S:.
?S:cpplast:
?S:	This variable has the same functionality as cppminus, only it applies to
?S:	cpprun and not cppstdin.
?S:.
?C:CPPSTDIN:
?C:	This symbol contains the first part of the string which will invoke
?C:	the C preprocessor on the standard input and produce to standard
?C:	output.	 Typical value of "cc -E" or "/lib/cpp", but it can also
?C:	call a wrapper. See CPPRUN.
?C:.
?C:CPPMINUS:
?C:	This symbol contains the second part of the string which will invoke
?C:	the C preprocessor on the standard input and produce to standard
?C:	output.  This symbol will have the value "-" if CPPSTDIN needs a minus
?C:	to specify standard input, otherwise the value is "".
?C:.
?C:CPPRUN:
?C:	This symbol contains the string which will invoke a C preprocessor on
?C:	the standard input and produce to standard output. It needs to end
?C:	with CPPLAST, after all other preprocessor flags have been specified.
?C:	The main difference with CPPSTDIN is that this program will never be a
?C:	pointer to a shell wrapper, i.e. it will be empty if no preprocessor is
?C:	available directly to the user. Note that it may well be different from
?C:	the preprocessor used to compile the C program.
?C:.
?C:CPPLAST:
?C:	This symbol is intended to be used along with CPPRUN in the same manner
?C:	symbol CPPMINUS is used with CPPSTDIN. It contains either "-" or "".
?C:.
?H:#define CPPSTDIN "$cppstdin"
?H:#define CPPMINUS "$cppminus"
?H:#define CPPRUN "$cpprun"
?H:#define CPPLAST "$cpplast"
?H:.
?F:cppstdin !testcpp.out !testcpp.c
?T:wrapper x_cpp x_minus ok
: see how we invoke the C preprocessor
echo " "
echo "Now, how can we feed standard input to your C preprocessor..." >&4
cat <<'EOT' >testcpp.c
#define ABC abc
#define XYZ xyz
ABC.XYZ
EOT
cd ..
if $test ! -f cppstdin; then
	echo "$startsh" >cppstdin
if $test "X$osname" = "Xaix" -a "X$gccversion" = X; then
?X: AIX cc -E doesn't show the absolute headerfile
?X: locations but we'll cheat by using the -M flag.
	echo 'cat >.$$.c; rm -f .$$.u; '"$cc"' ${1+"$@"} -M -c .$$.c 2>/dev/null; \
	test -s .$$.u && \
	awk '"'"'$2 ~ /\.h$/ { print "# 0 \""$2"\"" }'"'"' .$$.u; \
	rm -f .$$.o .$$.u; '"$cc"' -E ${1+"$@"} .$$.c; rm .$$.c' >> cppstdin
else
	echo 'cat >.$$.c; '"$cc"' -E ${1+"$@"} .$$.c; rm .$$.c' >>cppstdin
fi; else
	echo "Keeping your $hint cppstdin wrapper."
fi
chmod 755 cppstdin
$eunicefix cppstdin
wrapper=`pwd`/cppstdin
ok='false'
cd UU

?X:
?X: We'll run the cpp tests again if we don't have any valid C preprocessor
?X: yet or don't know how to proceed without a wrapper (in which case cpprun
?X: is empty and that's really annoying...)
?X:
if $test "X$cppstdin" != "X" && \
	$cppstdin $cppminus <testcpp.c >testcpp.out 2>&1 && \
	$contains 'abc.*xyz' testcpp.out >/dev/null 2>&1
then
	echo "You used to use $cppstdin $cppminus so we'll use that again."
	case "$cpprun" in
	'') echo "But let's see if we can live without a wrapper..." ;;
	*)
		if $cpprun $cpplast <testcpp.c >testcpp.out 2>&1 && \
			$contains 'abc.*xyz' testcpp.out >/dev/null 2>&1
		then
			echo "(And we'll use $cpprun $cpplast to preprocess directly.)"
			ok='true'
		else
			echo "(However, $cpprun $cpplast does not work, let's see...)"
		fi
		;;
	esac
else
	case "$cppstdin" in
	'') ;;
	*)
		echo "Good old $cppstdin $cppminus does not seem to be of any help..."
		;;
	esac
fi

if $ok; then
	: nothing
elif echo 'Maybe "'"$cc"' -E" will work...'; \
	$cc -E <testcpp.c >testcpp.out 2>&1; \
	$contains 'abc.*xyz' testcpp.out >/dev/null 2>&1 ; then
	echo "Yup, it does."
	x_cpp="$cc -E"
	x_minus='';
elif echo 'Nope...maybe "'"$cc"' -E -" will work...'; \
	$cc -E - <testcpp.c >testcpp.out 2>&1; \
	$contains 'abc.*xyz' testcpp.out >/dev/null 2>&1 ; then
	echo "Yup, it does."
	x_cpp="$cc -E"
	x_minus='-';
elif echo 'Nope...maybe "'"$cc"' -P" will work...'; \
	$cc -P <testcpp.c >testcpp.out 2>&1; \
	$contains 'abc.*xyz' testcpp.out >/dev/null 2>&1 ; then
	echo "Yipee, that works!"
	x_cpp="$cc -P"
	x_minus='';
elif echo 'Nope...maybe "'"$cc"' -P -" will work...'; \
	$cc -P - <testcpp.c >testcpp.out 2>&1; \
	$contains 'abc.*xyz' testcpp.out >/dev/null 2>&1 ; then
	echo "At long last!"
	x_cpp="$cc -P"
	x_minus='-';
elif echo 'No such luck, maybe "'$cpp'" will work...'; \
	$cpp <testcpp.c >testcpp.out 2>&1; \
	$contains 'abc.*xyz' testcpp.out >/dev/null 2>&1 ; then
	echo "It works!"
	x_cpp="$cpp"
	x_minus='';
elif echo 'Nixed again...maybe "'$cpp' -" will work...'; \
	$cpp - <testcpp.c >testcpp.out 2>&1; \
	$contains 'abc.*xyz' testcpp.out >/dev/null 2>&1 ; then
	echo "Hooray, it works!  I was beginning to wonder."
	x_cpp="$cpp"
	x_minus='-';
elif echo 'Uh-uh.  Time to get fancy.  Trying a wrapper...'; \
	$wrapper <testcpp.c >testcpp.out 2>&1; \
	$contains 'abc.*xyz' testcpp.out >/dev/null 2>&1 ; then
	x_cpp="$wrapper"
	x_minus=''
	echo "Eureka!"
else
	dflt=''
	rp="No dice.  I can't find a C preprocessor.  Name one:"
	. ./myread
	x_cpp="$ans"
	x_minus=''
	$x_cpp <testcpp.c >testcpp.out 2>&1
	if $contains 'abc.*xyz' testcpp.out >/dev/null 2>&1 ; then
		echo "OK, that will do." >&4
	else
echo "Sorry, I can't get that to work.  Go find one and rerun Configure." >&4
		exit 1
	fi
fi

case "$ok" in
false)
	cppstdin="$x_cpp"
	cppminus="$x_minus"
	cpprun="$x_cpp"
	cpplast="$x_minus"
?X:
?X: If /lib/cpp is used, try using a wrapper to increase our chances to have
?X: the C compiler and our $cppstdin agree on the same symbols... However,
?X: since cpprun is guaranteed not to be a wrapper, we must clear it if the
?X: only preprocessor we found was a wrapper, with all our luck...
?X:
	set X $x_cpp
	shift
	case "$1" in
	"$cpp")
		echo "Perhaps can we force $cc -E using a wrapper..."
		if $wrapper <testcpp.c >testcpp.out 2>&1; \
			$contains 'abc.*xyz' testcpp.out >/dev/null 2>&1
		then
			echo "Yup, we can."
			cppstdin="$wrapper"
			cppminus='';
		else
			echo "Nope, we'll have to live without it..."
		fi
		;;
	esac
	case "$cpprun" in
	"$wrapper")
		cpprun=''
		cpplast=''
		;;
	esac
	;;
esac

case "$cppstdin" in
"$wrapper"|'cppstdin') ;;
*) $rm -f $wrapper;;
esac
$rm -f testcpp.c testcpp.out

