1 files changed, 56 insertions, 0 deletions
diff --git a/test/std/input.output/file.streams/fstreams/filebuf.virtuals/pbackfail.pass.cpp b/test/std/input.output/file.streams/fstreams/filebuf.virtuals/pbackfail.pass.cpp
new file mode 100644
index 000000000000..4419cb51a6dc
--- /dev/null
+++ b/test/std/input.output/file.streams/fstreams/filebuf.virtuals/pbackfail.pass.cpp
@@ -0,0 +1,56 @@
+//===----------------------------------------------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is dual licensed under the MIT and the University of Illinois Open
+// Source Licenses. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+// <fstream>
+
+// int_type pbackfail(int_type c = traits::eof());
+
+// This test is not entirely portable
+
+#include <fstream>
+#include <cassert>
+
+template <class CharT>
+struct test_buf
+    : public std::basic_filebuf<CharT>
+{
+    typedef std::basic_filebuf<CharT>  base;
+    typedef typename base::char_type   char_type;
+    typedef typename base::int_type    int_type;
+    typedef typename base::traits_type traits_type;
+
+    char_type* eback() const {return base::eback();}
+    char_type* gptr()  const {return base::gptr();}
+    char_type* egptr() const {return base::egptr();}
+    void gbump(int n) {base::gbump(n);}
+
+    virtual int_type pbackfail(int_type c = traits_type::eof()) {return base::pbackfail(c);}
+};
+
+int main()
+{
+    {
+        test_buf<char> f;
+        assert(f.open("underflow.dat", std::ios_base::in) != 0);
+        assert(f.is_open());
+        assert(f.sbumpc() == '1');
+        assert(f.sgetc() == '2');
+        assert(f.pbackfail('a') == -1);
+    }
+    {
+        test_buf<char> f;
+        assert(f.open("underflow.dat", std::ios_base::in | std::ios_base::out) != 0);
+        assert(f.is_open());
+        assert(f.sbumpc() == '1');
+        assert(f.sgetc() == '2');
+        assert(f.pbackfail('a') == 'a');
+        assert(f.sbumpc() == 'a');
+        assert(f.sgetc() == '2');
+    }
+}