diff --git a/libcxx/docs/ReleaseNotes.rst b/libcxx/docs/ReleaseNotes.rst
index 56e856008cb3..2f040ed1d8d3 100644
--- a/libcxx/docs/ReleaseNotes.rst
+++ b/libcxx/docs/ReleaseNotes.rst
@@ -105,6 +105,9 @@ Deprecations and Removals
 
 - The ``_LIBCPP_ABI_OLD_LOGNORMAL_DISTRIBUTION`` macro has been removed.
 
+- The classes ``strstreambuf`` , ``istrstream``, ``ostrstream``, and ``strstream`` have been deprecated.
+  They have been deprecated in the Standard since C++98, but were never marked as deprecated in libc++.
+
 Upcoming Deprecations and Removals
 ----------------------------------
 
diff --git a/libcxx/include/strstream b/libcxx/include/strstream
index d0688fc4da19..01590445fea6 100644
--- a/libcxx/include/strstream
+++ b/libcxx/include/strstream
@@ -141,7 +141,7 @@ private:
 
 _LIBCPP_BEGIN_NAMESPACE_STD
 
-class _LIBCPP_TYPE_VIS strstreambuf
+class _LIBCPP_DEPRECATED _LIBCPP_TYPE_VIS strstreambuf
     : public streambuf
 {
 public:
@@ -237,7 +237,7 @@ strstreambuf::operator=(strstreambuf&& __rhs)
 
 #endif // _LIBCPP_CXX03_LANG
 
-class _LIBCPP_TYPE_VIS istrstream
+class _LIBCPP_DEPRECATED _LIBCPP_TYPE_VIS istrstream
     : public istream
 {
 public:
@@ -290,7 +290,7 @@ private:
     strstreambuf __sb_;
 };
 
-class _LIBCPP_TYPE_VIS ostrstream
+class _LIBCPP_DEPRECATED _LIBCPP_TYPE_VIS ostrstream
     : public ostream
 {
 public:
@@ -343,7 +343,7 @@ private:
     strstreambuf __sb_; // exposition only
 };
 
-class _LIBCPP_TYPE_VIS strstream
+class _LIBCPP_DEPRECATED _LIBCPP_TYPE_VIS strstream
     : public iostream
 {
 public:
diff --git a/libcxx/test/std/depr/depr.ios.members/io_state.pass.cpp b/libcxx/test/std/depr/depr.ios.members/io_state.pass.cpp
index 37b23fc5e8c3..9ed847683579 100644
--- a/libcxx/test/std/depr/depr.ios.members/io_state.pass.cpp
+++ b/libcxx/test/std/depr/depr.ios.members/io_state.pass.cpp
@@ -6,6 +6,10 @@
 //
 //===----------------------------------------------------------------------===//
 
+// REQUIRES: c++03 || c++11 || c++14
+
+// ADDITIONAL_COMPILE_FLAGS: -D_LIBCPP_DISABLE_DEPRECATION_WARNINGS
+
 // <ios>
 //
 // class ios_base
@@ -22,10 +26,8 @@
 
 int main(int, char**)
 {
-#if TEST_STD_VER <= 14
     std::strstream::io_state b = std::strstream::eofbit;
     assert(b == std::ios::eofbit);
-#endif
 
   return 0;
 }
diff --git a/libcxx/test/std/depr/depr.ios.members/open_mode.pass.cpp b/libcxx/test/std/depr/depr.ios.members/open_mode.pass.cpp
index 57a88c957673..de536c74c8dc 100644
--- a/libcxx/test/std/depr/depr.ios.members/open_mode.pass.cpp
+++ b/libcxx/test/std/depr/depr.ios.members/open_mode.pass.cpp
@@ -6,6 +6,10 @@
 //
 //===----------------------------------------------------------------------===//
 
+// REQUIRES: c++03 || c++11 || c++14
+
+// ADDITIONAL_COMPILE_FLAGS: -D_LIBCPP_DISABLE_DEPRECATION_WARNINGS
+
 // <ios>
 //
 // class ios_base
@@ -22,10 +26,8 @@
 
 int main(int, char**)
 {
-#if TEST_STD_VER <= 14
     std::strstream::open_mode b = std::strstream::app;
     assert(b == std::ios::app);
-#endif
 
   return 0;
 }
diff --git a/libcxx/test/std/depr/depr.ios.members/seek_dir.pass.cpp b/libcxx/test/std/depr/depr.ios.members/seek_dir.pass.cpp
index 5b48073bd2f1..b68e53694ddc 100644
--- a/libcxx/test/std/depr/depr.ios.members/seek_dir.pass.cpp
+++ b/libcxx/test/std/depr/depr.ios.members/seek_dir.pass.cpp
@@ -6,6 +6,10 @@
 //
 //===----------------------------------------------------------------------===//
 
+// REQUIRES: c++03 || c++11 || c++14
+
+// ADDITIONAL_COMPILE_FLAGS: -D_LIBCPP_DISABLE_DEPRECATION_WARNINGS
+
 // <ios>
 //
 // class ios_base
@@ -22,10 +26,8 @@
 
 int main(int, char**)
 {
-#if TEST_STD_VER <= 14
     std::strstream::seek_dir b = std::strstream::cur;
     assert(b == std::ios::cur);
-#endif
 
   return 0;
 }
diff --git a/libcxx/test/std/depr/depr.str.strstreams/depr.istrstream/depr.istrstream.cons/ccp.pass.cpp b/libcxx/test/std/depr/depr.str.strstreams/depr.istrstream/depr.istrstream.cons/ccp.pass.cpp
index 9823361b509e..b5ee0bfbecf0 100644
--- a/libcxx/test/std/depr/depr.str.strstreams/depr.istrstream/depr.istrstream.cons/ccp.pass.cpp
+++ b/libcxx/test/std/depr/depr.str.strstreams/depr.istrstream/depr.istrstream.cons/ccp.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
+// ADDITIONAL_COMPILE_FLAGS: -D_LIBCPP_DISABLE_DEPRECATION_WARNINGS
+
 // <strstream>
 
 // class istrstream
diff --git a/libcxx/test/std/depr/depr.str.strstreams/depr.istrstream/depr.istrstream.cons/ccp_size.pass.cpp b/libcxx/test/std/depr/depr.str.strstreams/depr.istrstream/depr.istrstream.cons/ccp_size.pass.cpp
index 0808f45ba52d..4d0d6731338a 100644
--- a/libcxx/test/std/depr/depr.str.strstreams/depr.istrstream/depr.istrstream.cons/ccp_size.pass.cpp
+++ b/libcxx/test/std/depr/depr.str.strstreams/depr.istrstream/depr.istrstream.cons/ccp_size.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
+// ADDITIONAL_COMPILE_FLAGS: -D_LIBCPP_DISABLE_DEPRECATION_WARNINGS
+
 // <strstream>
 
 // class istrstream
diff --git a/libcxx/test/std/depr/depr.str.strstreams/depr.istrstream/depr.istrstream.cons/cp.pass.cpp b/libcxx/test/std/depr/depr.str.strstreams/depr.istrstream/depr.istrstream.cons/cp.pass.cpp
index 681d7b7cf4c0..58980949732d 100644
--- a/libcxx/test/std/depr/depr.str.strstreams/depr.istrstream/depr.istrstream.cons/cp.pass.cpp
+++ b/libcxx/test/std/depr/depr.str.strstreams/depr.istrstream/depr.istrstream.cons/cp.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
+// ADDITIONAL_COMPILE_FLAGS: -D_LIBCPP_DISABLE_DEPRECATION_WARNINGS
+
 // <strstream>
 
 // class istrstream
diff --git a/libcxx/test/std/depr/depr.str.strstreams/depr.istrstream/depr.istrstream.cons/cp_size.pass.cpp b/libcxx/test/std/depr/depr.str.strstreams/depr.istrstream/depr.istrstream.cons/cp_size.pass.cpp
index 96f17b007279..e13e20e20f8c 100644
--- a/libcxx/test/std/depr/depr.str.strstreams/depr.istrstream/depr.istrstream.cons/cp_size.pass.cpp
+++ b/libcxx/test/std/depr/depr.str.strstreams/depr.istrstream/depr.istrstream.cons/cp_size.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
+// ADDITIONAL_COMPILE_FLAGS: -D_LIBCPP_DISABLE_DEPRECATION_WARNINGS
+
 // <strstream>
 
 // class istrstream
diff --git a/libcxx/test/std/depr/depr.str.strstreams/depr.istrstream/depr.istrstream.members/rdbuf.pass.cpp b/libcxx/test/std/depr/depr.str.strstreams/depr.istrstream/depr.istrstream.members/rdbuf.pass.cpp
index 80401264f302..449114a0f6a9 100644
--- a/libcxx/test/std/depr/depr.str.strstreams/depr.istrstream/depr.istrstream.members/rdbuf.pass.cpp
+++ b/libcxx/test/std/depr/depr.str.strstreams/depr.istrstream/depr.istrstream.members/rdbuf.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
+// ADDITIONAL_COMPILE_FLAGS: -D_LIBCPP_DISABLE_DEPRECATION_WARNINGS
+
 // <strstream>
 
 // class istrstream
diff --git a/libcxx/test/std/depr/depr.str.strstreams/depr.istrstream/depr.istrstream.members/str.pass.cpp b/libcxx/test/std/depr/depr.str.strstreams/depr.istrstream/depr.istrstream.members/str.pass.cpp
index 0ee341b226fb..e7c063750fb6 100644
--- a/libcxx/test/std/depr/depr.str.strstreams/depr.istrstream/depr.istrstream.members/str.pass.cpp
+++ b/libcxx/test/std/depr/depr.str.strstreams/depr.istrstream/depr.istrstream.members/str.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
+// ADDITIONAL_COMPILE_FLAGS: -D_LIBCPP_DISABLE_DEPRECATION_WARNINGS
+
 // <strstream>
 
 // class istrstream
diff --git a/libcxx/test/std/depr/depr.str.strstreams/depr.istrstream/depr.verify.cpp b/libcxx/test/std/depr/depr.str.strstreams/depr.istrstream/depr.verify.cpp
new file mode 100644
index 000000000000..2ab252e93494
--- /dev/null
+++ b/libcxx/test/std/depr/depr.str.strstreams/depr.istrstream/depr.verify.cpp
@@ -0,0 +1,15 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// <strstream>
+
+// check that istrstream is marked deprecated
+
+#include <strstream>
+
+std::istrstream s("abc"); // expected-warning {{'istrstream' is deprecated}}
diff --git a/libcxx/test/std/depr/depr.str.strstreams/depr.istrstream/types.pass.cpp b/libcxx/test/std/depr/depr.str.strstreams/depr.istrstream/types.pass.cpp
index 93cdbf677ec3..be1a9e1251ba 100644
--- a/libcxx/test/std/depr/depr.str.strstreams/depr.istrstream/types.pass.cpp
+++ b/libcxx/test/std/depr/depr.str.strstreams/depr.istrstream/types.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
+// ADDITIONAL_COMPILE_FLAGS: -D_LIBCPP_DISABLE_DEPRECATION_WARNINGS
+
 // <strstream>
 
 // class istrstream
diff --git a/libcxx/test/std/depr/depr.str.strstreams/depr.ostrstream/depr.ostrstream.cons/cp_size_mode.pass.cpp b/libcxx/test/std/depr/depr.str.strstreams/depr.ostrstream/depr.ostrstream.cons/cp_size_mode.pass.cpp
index 64a12ab3620a..8698983a7ebc 100644
--- a/libcxx/test/std/depr/depr.str.strstreams/depr.ostrstream/depr.ostrstream.cons/cp_size_mode.pass.cpp
+++ b/libcxx/test/std/depr/depr.str.strstreams/depr.ostrstream/depr.ostrstream.cons/cp_size_mode.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
+// ADDITIONAL_COMPILE_FLAGS: -D_LIBCPP_DISABLE_DEPRECATION_WARNINGS
+
 // <strstream>
 
 // class ostrstream
diff --git a/libcxx/test/std/depr/depr.str.strstreams/depr.ostrstream/depr.ostrstream.cons/default.pass.cpp b/libcxx/test/std/depr/depr.str.strstreams/depr.ostrstream/depr.ostrstream.cons/default.pass.cpp
index 6960f75c59fc..abbf6af7e11e 100644
--- a/libcxx/test/std/depr/depr.str.strstreams/depr.ostrstream/depr.ostrstream.cons/default.pass.cpp
+++ b/libcxx/test/std/depr/depr.str.strstreams/depr.ostrstream/depr.ostrstream.cons/default.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
+// ADDITIONAL_COMPILE_FLAGS: -D_LIBCPP_DISABLE_DEPRECATION_WARNINGS
+
 // <strstream>
 
 // class ostrstream
diff --git a/libcxx/test/std/depr/depr.str.strstreams/depr.ostrstream/depr.ostrstream.members/freeze.pass.cpp b/libcxx/test/std/depr/depr.str.strstreams/depr.ostrstream/depr.ostrstream.members/freeze.pass.cpp
index f52ff6c13ce2..854e68b17249 100644
--- a/libcxx/test/std/depr/depr.str.strstreams/depr.ostrstream/depr.ostrstream.members/freeze.pass.cpp
+++ b/libcxx/test/std/depr/depr.str.strstreams/depr.ostrstream/depr.ostrstream.members/freeze.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
+// ADDITIONAL_COMPILE_FLAGS: -D_LIBCPP_DISABLE_DEPRECATION_WARNINGS
+
 // <strstream>
 
 // class ostrstream
diff --git a/libcxx/test/std/depr/depr.str.strstreams/depr.ostrstream/depr.ostrstream.members/pcount.pass.cpp b/libcxx/test/std/depr/depr.str.strstreams/depr.ostrstream/depr.ostrstream.members/pcount.pass.cpp
index 080e05000c88..9830aeb6fc8c 100644
--- a/libcxx/test/std/depr/depr.str.strstreams/depr.ostrstream/depr.ostrstream.members/pcount.pass.cpp
+++ b/libcxx/test/std/depr/depr.str.strstreams/depr.ostrstream/depr.ostrstream.members/pcount.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
+// ADDITIONAL_COMPILE_FLAGS: -D_LIBCPP_DISABLE_DEPRECATION_WARNINGS
+
 // <strstream>
 
 // class ostrstream
diff --git a/libcxx/test/std/depr/depr.str.strstreams/depr.ostrstream/depr.ostrstream.members/rdbuf.pass.cpp b/libcxx/test/std/depr/depr.str.strstreams/depr.ostrstream/depr.ostrstream.members/rdbuf.pass.cpp
index df38ea977ed3..f9a859dd8dab 100644
--- a/libcxx/test/std/depr/depr.str.strstreams/depr.ostrstream/depr.ostrstream.members/rdbuf.pass.cpp
+++ b/libcxx/test/std/depr/depr.str.strstreams/depr.ostrstream/depr.ostrstream.members/rdbuf.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
+// ADDITIONAL_COMPILE_FLAGS: -D_LIBCPP_DISABLE_DEPRECATION_WARNINGS
+
 // <strstream>
 
 // class ostrstream
diff --git a/libcxx/test/std/depr/depr.str.strstreams/depr.ostrstream/depr.ostrstream.members/str.pass.cpp b/libcxx/test/std/depr/depr.str.strstreams/depr.ostrstream/depr.ostrstream.members/str.pass.cpp
index 5de41cd72306..72f665af5851 100644
--- a/libcxx/test/std/depr/depr.str.strstreams/depr.ostrstream/depr.ostrstream.members/str.pass.cpp
+++ b/libcxx/test/std/depr/depr.str.strstreams/depr.ostrstream/depr.ostrstream.members/str.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
+// ADDITIONAL_COMPILE_FLAGS: -D_LIBCPP_DISABLE_DEPRECATION_WARNINGS
+
 // <strstream>
 
 // class ostrstream
diff --git a/libcxx/test/std/depr/depr.str.strstreams/depr.ostrstream/depr.verify.cpp b/libcxx/test/std/depr/depr.str.strstreams/depr.ostrstream/depr.verify.cpp
new file mode 100644
index 000000000000..e0c805fee107
--- /dev/null
+++ b/libcxx/test/std/depr/depr.str.strstreams/depr.ostrstream/depr.verify.cpp
@@ -0,0 +1,15 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// <strstream>
+
+// check that ostrstream is marked deprecated
+
+#include <strstream>
+
+std::ostrstream s; // expected-warning {{'ostrstream' is deprecated}}
diff --git a/libcxx/test/std/depr/depr.str.strstreams/depr.ostrstream/types.pass.cpp b/libcxx/test/std/depr/depr.str.strstreams/depr.ostrstream/types.pass.cpp
index 3e753702065b..6a71c44a90cf 100644
--- a/libcxx/test/std/depr/depr.str.strstreams/depr.ostrstream/types.pass.cpp
+++ b/libcxx/test/std/depr/depr.str.strstreams/depr.ostrstream/types.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
+// ADDITIONAL_COMPILE_FLAGS: -D_LIBCPP_DISABLE_DEPRECATION_WARNINGS
+
 // <strstream>
 
 // class ostrstream
diff --git a/libcxx/test/std/depr/depr.str.strstreams/depr.strstream/depr.strstream.cons/cp_size_mode.pass.cpp b/libcxx/test/std/depr/depr.str.strstreams/depr.strstream/depr.strstream.cons/cp_size_mode.pass.cpp
index 96c2890c2cc0..a85e1328b351 100644
--- a/libcxx/test/std/depr/depr.str.strstreams/depr.strstream/depr.strstream.cons/cp_size_mode.pass.cpp
+++ b/libcxx/test/std/depr/depr.str.strstreams/depr.strstream/depr.strstream.cons/cp_size_mode.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
+// ADDITIONAL_COMPILE_FLAGS: -D_LIBCPP_DISABLE_DEPRECATION_WARNINGS
+
 // <strstream>
 
 // class strstream
diff --git a/libcxx/test/std/depr/depr.str.strstreams/depr.strstream/depr.strstream.cons/default.pass.cpp b/libcxx/test/std/depr/depr.str.strstreams/depr.strstream/depr.strstream.cons/default.pass.cpp
index 907985b3de40..390162ef0f18 100644
--- a/libcxx/test/std/depr/depr.str.strstreams/depr.strstream/depr.strstream.cons/default.pass.cpp
+++ b/libcxx/test/std/depr/depr.str.strstreams/depr.strstream/depr.strstream.cons/default.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
+// ADDITIONAL_COMPILE_FLAGS: -D_LIBCPP_DISABLE_DEPRECATION_WARNINGS
+
 // <strstream>
 
 // class strstream
diff --git a/libcxx/test/std/depr/depr.str.strstreams/depr.strstream/depr.strstream.dest/rdbuf.pass.cpp b/libcxx/test/std/depr/depr.str.strstreams/depr.strstream/depr.strstream.dest/rdbuf.pass.cpp
index 210e73057f08..3fe277a48cbb 100644
--- a/libcxx/test/std/depr/depr.str.strstreams/depr.strstream/depr.strstream.dest/rdbuf.pass.cpp
+++ b/libcxx/test/std/depr/depr.str.strstreams/depr.strstream/depr.strstream.dest/rdbuf.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
+// ADDITIONAL_COMPILE_FLAGS: -D_LIBCPP_DISABLE_DEPRECATION_WARNINGS
+
 // <strstream>
 
 // class strstream
diff --git a/libcxx/test/std/depr/depr.str.strstreams/depr.strstream/depr.strstream.oper/freeze.pass.cpp b/libcxx/test/std/depr/depr.str.strstreams/depr.strstream/depr.strstream.oper/freeze.pass.cpp
index f5de291a8797..263fddef6c34 100644
--- a/libcxx/test/std/depr/depr.str.strstreams/depr.strstream/depr.strstream.oper/freeze.pass.cpp
+++ b/libcxx/test/std/depr/depr.str.strstreams/depr.strstream/depr.strstream.oper/freeze.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
+// ADDITIONAL_COMPILE_FLAGS: -D_LIBCPP_DISABLE_DEPRECATION_WARNINGS
+
 // <strstream>
 
 // class strstream
diff --git a/libcxx/test/std/depr/depr.str.strstreams/depr.strstream/depr.strstream.oper/pcount.pass.cpp b/libcxx/test/std/depr/depr.str.strstreams/depr.strstream/depr.strstream.oper/pcount.pass.cpp
index abf928ffe5aa..b053cf128ab4 100644
--- a/libcxx/test/std/depr/depr.str.strstreams/depr.strstream/depr.strstream.oper/pcount.pass.cpp
+++ b/libcxx/test/std/depr/depr.str.strstreams/depr.strstream/depr.strstream.oper/pcount.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
+// ADDITIONAL_COMPILE_FLAGS: -D_LIBCPP_DISABLE_DEPRECATION_WARNINGS
+
 // <strstream>
 
 // class strstream
diff --git a/libcxx/test/std/depr/depr.str.strstreams/depr.strstream/depr.strstream.oper/str.pass.cpp b/libcxx/test/std/depr/depr.str.strstreams/depr.strstream/depr.strstream.oper/str.pass.cpp
index 59ee9095ec6a..3d251d9a99cd 100644
--- a/libcxx/test/std/depr/depr.str.strstreams/depr.strstream/depr.strstream.oper/str.pass.cpp
+++ b/libcxx/test/std/depr/depr.str.strstreams/depr.strstream/depr.strstream.oper/str.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
+// ADDITIONAL_COMPILE_FLAGS: -D_LIBCPP_DISABLE_DEPRECATION_WARNINGS
+
 // <strstream>
 
 // class strstream
diff --git a/libcxx/test/std/depr/depr.str.strstreams/depr.strstream/depr.verify.cpp b/libcxx/test/std/depr/depr.str.strstreams/depr.strstream/depr.verify.cpp
new file mode 100644
index 000000000000..03655226a54b
--- /dev/null
+++ b/libcxx/test/std/depr/depr.str.strstreams/depr.strstream/depr.verify.cpp
@@ -0,0 +1,15 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// <strstream>
+
+// check that strstream is marked deprecated
+
+#include <strstream>
+
+std::strstream s; // expected-warning {{'strstream' is deprecated}}
diff --git a/libcxx/test/std/depr/depr.str.strstreams/depr.strstream/types.pass.cpp b/libcxx/test/std/depr/depr.str.strstreams/depr.strstream/types.pass.cpp
index 3e9705366428..fb543841e8f3 100644
--- a/libcxx/test/std/depr/depr.str.strstreams/depr.strstream/types.pass.cpp
+++ b/libcxx/test/std/depr/depr.str.strstreams/depr.strstream/types.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
+// ADDITIONAL_COMPILE_FLAGS: -D_LIBCPP_DISABLE_DEPRECATION_WARNINGS
+
 // <strstream>
 
 // class strstream
diff --git a/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.cons/ccp_size.pass.cpp b/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.cons/ccp_size.pass.cpp
index 57969fb374ff..8f81707973d8 100644
--- a/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.cons/ccp_size.pass.cpp
+++ b/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.cons/ccp_size.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
+// ADDITIONAL_COMPILE_FLAGS: -D_LIBCPP_DISABLE_DEPRECATION_WARNINGS
+
 // <strstream>
 
 // class strstreambuf
diff --git a/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.cons/cp_size_cp.pass.cpp b/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.cons/cp_size_cp.pass.cpp
index 4fe716006c19..25a9617dcdaf 100644
--- a/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.cons/cp_size_cp.pass.cpp
+++ b/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.cons/cp_size_cp.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
+// ADDITIONAL_COMPILE_FLAGS: -D_LIBCPP_DISABLE_DEPRECATION_WARNINGS
+
 // <strstream>
 
 // class strstreambuf
diff --git a/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.cons/cscp_size.pass.cpp b/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.cons/cscp_size.pass.cpp
index 001151c367d7..fc3386ff5575 100644
--- a/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.cons/cscp_size.pass.cpp
+++ b/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.cons/cscp_size.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
+// ADDITIONAL_COMPILE_FLAGS: -D_LIBCPP_DISABLE_DEPRECATION_WARNINGS
+
 // <strstream>
 
 // class strstreambuf
diff --git a/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.cons/cucp_size.pass.cpp b/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.cons/cucp_size.pass.cpp
index b4efb11c9881..a74c504fd278 100644
--- a/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.cons/cucp_size.pass.cpp
+++ b/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.cons/cucp_size.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
+// ADDITIONAL_COMPILE_FLAGS: -D_LIBCPP_DISABLE_DEPRECATION_WARNINGS
+
 // <strstream>
 
 // class strstreambuf
diff --git a/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.cons/custom_alloc.pass.cpp b/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.cons/custom_alloc.pass.cpp
index 83e3009ce4f8..756427df4820 100644
--- a/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.cons/custom_alloc.pass.cpp
+++ b/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.cons/custom_alloc.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
+// ADDITIONAL_COMPILE_FLAGS: -D_LIBCPP_DISABLE_DEPRECATION_WARNINGS
+
 // <strstream>
 
 // class strstreambuf
diff --git a/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.cons/default.pass.cpp b/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.cons/default.pass.cpp
index 844f31e4a454..81924c995b15 100644
--- a/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.cons/default.pass.cpp
+++ b/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.cons/default.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
+// ADDITIONAL_COMPILE_FLAGS: -D_LIBCPP_DISABLE_DEPRECATION_WARNINGS
+
 // <strstream>
 
 // class strstreambuf
diff --git a/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.cons/scp_size_scp.pass.cpp b/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.cons/scp_size_scp.pass.cpp
index afe34072cb91..b8991a8fc433 100644
--- a/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.cons/scp_size_scp.pass.cpp
+++ b/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.cons/scp_size_scp.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
+// ADDITIONAL_COMPILE_FLAGS: -D_LIBCPP_DISABLE_DEPRECATION_WARNINGS
+
 // <strstream>
 
 // class strstreambuf
diff --git a/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.cons/ucp_size_ucp.pass.cpp b/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.cons/ucp_size_ucp.pass.cpp
index e7b8d6d139cf..1d3463f3cac1 100644
--- a/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.cons/ucp_size_ucp.pass.cpp
+++ b/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.cons/ucp_size_ucp.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
+// ADDITIONAL_COMPILE_FLAGS: -D_LIBCPP_DISABLE_DEPRECATION_WARNINGS
+
 // <strstream>
 
 // class strstreambuf
diff --git a/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.members/freeze.pass.cpp b/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.members/freeze.pass.cpp
index 54587c5941a3..93eec8dde397 100644
--- a/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.members/freeze.pass.cpp
+++ b/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.members/freeze.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
+// ADDITIONAL_COMPILE_FLAGS: -D_LIBCPP_DISABLE_DEPRECATION_WARNINGS
+
 // <strstream>
 
 // class strstreambuf
diff --git a/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.members/overflow.pass.cpp b/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.members/overflow.pass.cpp
index a0a27fa7a600..5b973cff0ce0 100644
--- a/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.members/overflow.pass.cpp
+++ b/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.members/overflow.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
+// ADDITIONAL_COMPILE_FLAGS: -D_LIBCPP_DISABLE_DEPRECATION_WARNINGS
+
 // <strstream>
 
 // class strstreambuf
diff --git a/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.members/pcount.pass.cpp b/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.members/pcount.pass.cpp
index 1bf17d94ed02..b64c9dcb4447 100644
--- a/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.members/pcount.pass.cpp
+++ b/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.members/pcount.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
+// ADDITIONAL_COMPILE_FLAGS: -D_LIBCPP_DISABLE_DEPRECATION_WARNINGS
+
 // <strstream>
 
 // class strstreambuf
diff --git a/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.members/str.pass.cpp b/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.members/str.pass.cpp
index 841334b373f3..d6c8b8e7e11b 100644
--- a/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.members/str.pass.cpp
+++ b/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.members/str.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
+// ADDITIONAL_COMPILE_FLAGS: -D_LIBCPP_DISABLE_DEPRECATION_WARNINGS
+
 // <strstream>
 
 // class strstreambuf
diff --git a/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.virtuals/overflow.pass.cpp b/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.virtuals/overflow.pass.cpp
index b2267a0aac22..37109c7e942c 100644
--- a/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.virtuals/overflow.pass.cpp
+++ b/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.virtuals/overflow.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
+// ADDITIONAL_COMPILE_FLAGS: -D_LIBCPP_DISABLE_DEPRECATION_WARNINGS
+
 // <strstream>
 
 // class strstreambuf
diff --git a/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.virtuals/pbackfail.pass.cpp b/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.virtuals/pbackfail.pass.cpp
index 1f92b2057da8..698953f7121a 100644
--- a/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.virtuals/pbackfail.pass.cpp
+++ b/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.virtuals/pbackfail.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
+// ADDITIONAL_COMPILE_FLAGS: -D_LIBCPP_DISABLE_DEPRECATION_WARNINGS
+
 // <strstream>
 
 // class strstreambuf
diff --git a/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.virtuals/seekoff.pass.cpp b/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.virtuals/seekoff.pass.cpp
index 94b1346ed82f..d98e6f73f7aa 100644
--- a/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.virtuals/seekoff.pass.cpp
+++ b/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.virtuals/seekoff.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
+// ADDITIONAL_COMPILE_FLAGS: -D_LIBCPP_DISABLE_DEPRECATION_WARNINGS
+
 // <strstream>
 
 // class strstreambuf
diff --git a/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.virtuals/seekpos.pass.cpp b/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.virtuals/seekpos.pass.cpp
index f7e96ed4020c..be88f5aecc5c 100644
--- a/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.virtuals/seekpos.pass.cpp
+++ b/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.virtuals/seekpos.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
+// ADDITIONAL_COMPILE_FLAGS: -D_LIBCPP_DISABLE_DEPRECATION_WARNINGS
+
 // <strstream>
 
 // class strstreambuf
diff --git a/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.virtuals/setbuf.pass.cpp b/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.virtuals/setbuf.pass.cpp
index e663862d3907..ce7612bc66a9 100644
--- a/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.virtuals/setbuf.pass.cpp
+++ b/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.virtuals/setbuf.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
+// ADDITIONAL_COMPILE_FLAGS: -D_LIBCPP_DISABLE_DEPRECATION_WARNINGS
+
 // <strstream>
 
 // class strstreambuf
diff --git a/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.virtuals/underflow.pass.cpp b/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.virtuals/underflow.pass.cpp
index 6aa4b434253b..4fc79b575c7a 100644
--- a/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.virtuals/underflow.pass.cpp
+++ b/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.strstreambuf.virtuals/underflow.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
+// ADDITIONAL_COMPILE_FLAGS: -D_LIBCPP_DISABLE_DEPRECATION_WARNINGS
+
 // <strstream>
 
 // class strstreambuf
diff --git a/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.verify.cpp b/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.verify.cpp
new file mode 100644
index 000000000000..a598acbba8c8
--- /dev/null
+++ b/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/depr.verify.cpp
@@ -0,0 +1,15 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// <strstream>
+
+// check that strstreambuf is marked deprecated
+
+#include <strstream>
+
+std::strstreambuf s; // expected-warning {{'strstreambuf' is deprecated}}
diff --git a/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/types.pass.cpp b/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/types.pass.cpp
index bf86406c96f4..bc312cbbb225 100644
--- a/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/types.pass.cpp
+++ b/libcxx/test/std/depr/depr.str.strstreams/depr.strstreambuf/types.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
+// ADDITIONAL_COMPILE_FLAGS: -D_LIBCPP_DISABLE_DEPRECATION_WARNINGS
+
 // <strstream>
 
 // class strstreambuf