Add probe for C99-style static inline.

[metaconfig.git] / U / compline / d_static_inline.U

?RCS: $Id: d_static_inline.U,v $
?RCS:
?RCS: Copyright (c) 2010 Andrew Dougherty
?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 3.0.
?RCS:
?RCS: Original Author: Andy Dougherty <doughera@lafayette.edu>
?RCS:
?MAKE:d_static_inline perl_static_inline: Compile Setvar gccversion \
	cat echo run hint rm rm_try
?MAKE:	-pick add $@ %<
?S:d_static_inline:
?S:	This variable conditionally defines the HAS_STATIC_INLINE symbol,
?S:	which indicates that the C compiler supports C99-style static
?S:	inline.  That is, the function can't be called from another
?S:	translation unit.
?S:.
?S:perl_static_inline:
?S:	This variable defines the PERL_STATIC_INLINE symbol to
?S:	the best-guess incantation to use for static inline functions.
?S:	Possibilities include
?S:		static inline       (c99)
?S:		static __inline__   (gcc -ansi)
?S:		static __inline     (MSVC)
?S:		static _inline      (older MSVC)
?S:		static              (c89 compilers)
?S:.
?C:HAS_STATIC_INLINE :
?C:	This symbol, if defined, indicates that the C compiler supports
?C:	C99-style static inline.  That is, the function can't be called
?C:	from another translation unit.
?C:.
?C:PERL_STATIC_INLINE:
?C:	This symbol gives the best-guess incantation to use for static
?C:	inline functions.  If HAS_STATIC_INLINE is defined, this will
?C:	give C99-style inline.  If HAS_STATIC_INLINE is not defined,
?C:	this will give a plain 'static'.  It will always be defined
?C:	to something that gives static linkage.
?C:	Possibilities include
?C:		static inline       (c99)
?C:		static __inline__   (gcc -ansi)
?C:		static __inline     (MSVC)
?C:		static _inline      (older MSVC)
?C:		static              (c89 compilers)
?C:.
?H:#$d_static_inline HAS_STATIC_INLINE				/**/
?H:#define PERL_STATIC_INLINE $perl_static_inline	/**/
?H:.
?LINT:set d_static_inline
?T:inline xxx
?F:!try
: see what flavor, if any, of static inline is supported
echo " "
echo "Checking to see if your system supports static inline..."
?X:	Build two programs.  The first uses static inline in file a.c and
?X:	should work.  The second also includes b.c which tries to link against
?X:	the static function in a.c.  This should fail.
?X:.
$cat > try.c <<'EOCP'
#include <stdlib.h>
extern int f_via_a(int x);
extern int f_via_b(int x);
int main(int argc, char **argv)
{
    int y;

    y = f_via_a(0);
#ifdef USE_B
    y = f_via_b(0);
#endif
    if (y == 42) {
        return EXIT_SUCCESS;
    }
    else {
        return EXIT_FAILURE;
    }
}
EOCP
$cat > a.c <<'EOCP'
static INLINE int f(int x) {
    int y;
    y = x + 42;
    return y;
}

int f_via_a(int x)
{
    return f(x);
}
EOCP
$cat > b.c <<'EOCP'
extern int f(int x);

int f_via_b(int x)
{
    return f(x);
}
EOCP

# Respect a hint (or previous) value for perl_static_inline, if there is one.
case "$perl_static_inline" in
'')	# Check the various possibilities, and break out on success.
	# For gcc, prefer __inline__, which will still permit 
	# cflags.SH to add in -ansi.
	case "$gccversion" in
		'') xxx="inline __inline__ __inline _inline";;
		*)  xxx="__inline__ inline __inline _inline";;
	esac
	for inline in $xxx; do
		set try -DINLINE=$inline a.c
		if eval $compile && $run ./try; then
			# Now make sure there is no external linkage of static
			# functions
			set try -DINLINE=$inline -DUSE_B a.c b.c
			if eval $compile && $run ./try; then
				$echo "Your compiler supports static $inline, " >&4
				$echo "but it also creates an external definition," >&4
				$echo "so I won't use it." >&4
				val=$undef
			else
				$echo "Your compiler supports static $inline." >&4
				val=$define
				perl_static_inline="static $inline";
				break;
			fi
		else
			$echo "Your compiler does NOT support static $inline." >&4
			val="$undef"
		fi
	done
	;;
*inline*) # Some variant of inline exists.
	echo "Keeping your $hint value of $perl_static_inline."
	val=$define
	;;
static)  # No inline capabilities
	echo "Keeping your $hint value of $perl_static_inline."
	val=$undef
	;;
*)  # Unrecognized previous value -- blindly trust the supplied
	# value and hope it makes sense.  Use old value for
	# d_static_inline, if there is one.
	echo "Keeping your $hint value of $perl_static_inline."
	case "$d_static_inline" in
		'') val=$define ;;
		*)  val=$d_static_inline ;;
	esac
	;;
esac
# Fallback to plain 'static' if nothing worked.
case "$perl_static_inline" in
'')
	perl_static_inline="static"
	val=$undef
	;;
esac
set d_static_inline
eval $setvar
$rm -f a.[co] b.[co]
$rm_try