diff --git a/libcxx/include/support/win32/locale_win32.h b/libcxx/include/support/win32/locale_win32.h
--- a/libcxx/include/support/win32/locale_win32.h
+++ b/libcxx/include/support/win32/locale_win32.h
@@ -201,8 +201,8 @@
 #define strtof_l _strtof_l
 #define strtold_l _strtold_l
 #else
-float strtof_l(const char*, char**, locale_t);
-long double strtold_l(const char*, char**, locale_t);
+_LIBCPP_FUNC_VIS float strtof_l(const char*, char**, locale_t);
+_LIBCPP_FUNC_VIS long double strtold_l(const char*, char**, locale_t);
 #endif
 inline _LIBCPP_INLINE_VISIBILITY
 int