dnl CF_FUNC_WAIT version: 4 updated: 2021/01/02 09:31:20
dnl ------------
dnl Test for the presence of <sys/wait.h>, 'union wait', arg-type of 'wait()'
dnl and/or 'waitpid()'.
dnl
dnl Note that we cannot simply grep for 'union wait' in the wait.h file,
dnl because some Posix systems turn this on only when a BSD variable is
dnl defined.
dnl
dnl I don't use AC_HEADER_SYS_WAIT, because it defines HAVE_SYS_WAIT_H, which
dnl would conflict with an attempt to test that header directly.
dnl
AC_DEFUN([CF_FUNC_WAIT],
[
AC_REQUIRE([CF_UNION_WAIT])
if test "$cf_cv_type_unionwait" = yes; then

	AC_MSG_CHECKING(if union wait can be used as wait-arg)
	AC_CACHE_VAL(cf_cv_arg_union_wait,[
		AC_TRY_COMPILE($cf_wait_headers,
 			[union wait x; wait(&x)],
			[cf_cv_arg_union_wait=yes],
			[cf_cv_arg_union_wait=no])
		])
	AC_MSG_RESULT($cf_cv_arg_union_wait)
	test "$cf_cv_arg_union_wait" = yes && AC_DEFINE(WAIT_USES_UNION,1,[Define to 1 if wait() uses a union parameter])

	AC_MSG_CHECKING(if union wait can be used as waitpid-arg)
	AC_CACHE_VAL(cf_cv_arg_union_waitpid,[
		AC_TRY_COMPILE($cf_wait_headers,
 			[union wait x; waitpid(0, &x, 0)],
			[cf_cv_arg_union_waitpid=yes],
			[cf_cv_arg_union_waitpid=no])
		])
	AC_MSG_RESULT($cf_cv_arg_union_waitpid)
	test "$cf_cv_arg_union_waitpid" = yes && AC_DEFINE(WAITPID_USES_UNION,1,[Define to 1 if waitpid() uses a union parameter])

fi
])dnl
