dnl $Id: vacopy.m4 719 2008-10-29 09:08:42Z mgrimm $

dnl Check for means to copy variable argument lists. After this check,
dnl va_copy will at least be defined to something working.
dnl This requires stdarg.h, which is assumed to exist.

dnl Copyright (c) 2008 Moritz Grimm <mgrimm@mrsserver.net>
dnl
dnl Permission to use, copy, modify, and distribute this software for any
dnl purpose with or without fee is hereby granted, provided that the above
dnl copyright notice and this permission notice appear in all copies.
dnl
dnl THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
dnl WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
dnl MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
dnl ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
dnl WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
dnl ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
dnl OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.

dnl AX_FUNC_VA_COPY

AC_DEFUN([AX_FUNC_VA_COPY],
[
AC_MSG_CHECKING([for means to copy variable argument lists])
AC_CACHE_VAL([local_ac_cv_func_va_copy],
[
	AC_LINK_IFELSE(
		[AC_LANG_PROGRAM(
		[[
		  #include <stdarg.h>
		]],
		[[
		  va_list ap, ap2;
		  va_copy(ap2, ap);
		]])],
		[local_ac_cv_func_va_copy=va_copy],
		[AC_LINK_IFELSE(
			[AC_LANG_PROGRAM(
			[[
			  #include <stdarg.h>
			]],
			[[
			  va_list ap, ap2;
			  __va_copy(ap2, ap);
			]])],
			[local_ac_cv_func_va_copy=__va_copy],
			[local_ac_cv_func_va_copy=memcpy]
		)]
	)
])
AH_TEMPLATE([va_copy],
	[Define vararg lists copy function if necessary.])
case "${local_ac_cv_func_va_copy}" in
	va_copy)
		AC_MSG_RESULT([va_copy])
		;;
	__va_copy)
		AC_MSG_RESULT([__va_copy])
		AC_DEFINE([va_copy],
			[__va_copy])
		;;
	memcpy)
		AC_MSG_RESULT([memcpy])
		AC_DEFINE([va_copy(dst, src)],
			[memcpy(&(dst), &(src), sizeof(va_list))])
		;;
	*)
		dnl Cannot happen unless the cache value is corrupt.
		;;
esac
])