new test, fixing check of old one

Author: NinaRanns

libstdc++-v3/testsuite/18_support/contracts/invoke_default_cvh.cc

@@ -21,19 +21,20 @@
 #include <contracts>
 #include <testsuite_hooks.h>
 
-bool custom_called = 1;
+bool custom_called = false;
 
 
 void handle_contract_violation(const std::contracts::contract_violation& v)
 {
   invoke_default_contract_violation_handler(v);
+  custom_called = true;
 }
 
 void f(int i) pre (i>10) {};
 
 int main()
 {
   f(0);
-  VERIFY(custom_called == 1);
+  VERIFY(custom_called);
 }
 // { dg-output "contract violation in function f at .*(\n|\r\n|\r)" }

libstdc++-v3/testsuite/18_support/contracts/invoke_default_cvh2.cc

@@ -0,0 +1,71 @@
+// Copyright (C) 2020-2025 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 "-g0 -fcontracts -fcontracts-nonattr -fcontract-evaluation-semantic=observe" }
+// { dg-do run { target c++2a } }
+
+#include <contracts>
+#include <testsuite_hooks.h>
+#include <iostream>
+#include <sstream>
+
+
+struct checking_buf
+  : public std::streambuf
+{
+  bool written = false;
+
+  checking_buf() = default;
+
+  virtual int_type
+  overflow(int_type)
+  {
+    written = true;
+    return int_type();
+  }
+
+  std::streamsize xsputn(const char* s, std::streamsize count)
+  {
+    written = true;
+    return count;
+  }
+
+};
+
+
+bool custom_called = false;
+
+
+void handle_contract_violation(const std::contracts::contract_violation& v)
+{
+  custom_called = true;
+}
+
+
+
+
+void f(int i) pre (i>10) {};
+
+int main()
+{
+  checking_buf buf;
+  std::cerr.rdbuf(&buf);
+
+  f(0);
+  VERIFY(!buf.written);
+}
+