michael@0: # Checks whether the compiler implements namespaces
michael@0: AC_DEFUN([AC_CXX_NAMESPACES],
michael@0:  [AC_CACHE_CHECK(whether the compiler implements namespaces,
michael@0:                  ac_cv_cxx_namespaces,
michael@0:                  [AC_LANG_SAVE
michael@0:                   AC_LANG_CPLUSPLUS
michael@0:                   AC_TRY_COMPILE([namespace Outer {
michael@0:                                     namespace Inner { int i = 0; }}],
michael@0:                                  [using namespace Outer::Inner; return i;],
michael@0:                                  ac_cv_cxx_namespaces=yes,
michael@0:                                  ac_cv_cxx_namespaces=no)
michael@0:                   AC_LANG_RESTORE])
michael@0:   if test "$ac_cv_cxx_namespaces" = yes; then
michael@0:     AC_DEFINE(HAVE_NAMESPACES, 1, [define if the compiler implements namespaces])
michael@0:   fi])