ac_cxx_namespaces.m4

实现了poll/epoll/devpoll等C++封装

dnl @synopsis AC_CXX_NAMESPACES
dnl
dnl If the compiler can prevent names clashes using namespaces, define
dnl HAVE_NAMESPACES.
dnl
dnl @version $Id: ac_cxx_namespaces.m4,v 1.1 2000/07/12 08:44:29 rssh Exp $
dnl @author Luc Maisonobe
dnl
AC_DEFUN(AC_CXX_NAMESPACES,
[AC_CACHE_CHECK(whether the compiler implements namespaces,
ac_cv_cxx_namespaces,
[AC_LANG_SAVE
 AC_LANG_CPLUSPLUS
 AC_TRY_COMPILE([namespace Outer { namespace Inner { int i = 0; }}],
                [using namespace Outer::Inner; return i;],
 ac_cv_cxx_namespaces=yes, ac_cv_cxx_namespaces=no)
 AC_LANG_RESTORE
])
if test "$ac_cv_cxx_namespaces" = yes; then
  AC_DEFINE(HAVE_NAMESPACES,,[define if the compiler implements namespaces])
fi
])