@@ -4011,6 +4011,8 @@ _GLIBCXX_BEGIN_NAMESPACE_ALGO
using _Cat = typename iterator_traits<_InputIterator>::iterator_category;
if constexpr (is_base_of_v<random_access_iterator_tag, _Cat>)
{
+ if (__n2 <= 0)
+ return __first;
auto __last = __first + __n2;
std::for_each(__first, __last, std::move(__f));
return __last;
new file mode 100644
@@ -0,0 +1,44 @@
+// Copyright (C) 2019 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library. This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License along
+// with this library; see the file COPYING3. If not see
+// <http://www.gnu.org/licenses/>.
+
+// { dg-options "-std=gnu++17" }
+// { dg-do run { target c++17 } }
+
+#include <algorithm>
+#include <debug/vector>
+#include <debug/list>
+
+void
+test01()
+{
+ __gnu_debug::vector<int> v{1, 2, 3};
+ std::for_each_n(v.begin(), -2, [](int){});
+}
+
+void
+test02()
+{
+ __gnu_debug::list<int> l{1, 2, 3};
+ std::for_each_n(l.begin(), -2, [](int){});
+}
+
+int
+main()
+{
+ test01();
+ test02();
+}