#endif
-#if @REPLACE_DUP@
-# if !(defined __cplusplus && defined GNULIB_NAMESPACE)
-# define dup rpl_dup
-# endif
+#if @GNULIB_DUP@
+# if @REPLACE_DUP@
+# if !(defined __cplusplus && defined GNULIB_NAMESPACE)
+# define dup rpl_dup
+# endif
_GL_FUNCDECL_RPL (dup, int, (int oldfd));
_GL_CXXALIAS_RPL (dup, int, (int oldfd));
-#else
+# else
_GL_CXXALIAS_SYS (dup, int, (int oldfd));
-#endif
+# endif
_GL_CXXALIASWARN (dup);
+#elif defined GNULIB_POSIXCHECK
+# undef dup
+# if HAVE_RAW_DECL_DUP
+_GL_WARN_ON_USE (dup, "dup is unportable - "
+ "use gnulib module dup for portability");
+# endif
+#endif
#if @GNULIB_DUP2@