QProcess: Ensure that the stdin buffer is cleared on start()

The buffer may have been left dirty if we were unable to write all the
data to the child process in the previous run. So ensure we clear it
before starting a new one. We already did that for stdout and stderr,
for some reason.

Task-number: QTBUG-44517
Change-Id: I1a800c709d3543699131ffff13c419da3bbffacf
Reviewed-by: Kai Koehne <kai.koehne@theqtcompany.com>
Reviewed-by: Joerg Bornemann <joerg.bornemann@theqtcompany.com>
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@theqtcompany.com>

1 files changed, 62 insertions, 0 deletions

diff --git a/tests/auto/corelib/io/qprocess/testProcessHang/main.cpp b/tests/auto/corelib/io/qprocess/testProcessHang/main.cpp
new file mode 100644
index 0000000000..e06502f738
--- /dev/null
+++ b/tests/auto/corelib/io/qprocess/testProcessHang/main.cpp
@@ -0,0 +1,62 @@
+/****************************************************************************
+**
+** Copyright (C) 2015 Intel Corporation.
+** Contact: http://www.qt.io/licensing/
+**
+** This file is part of the test suite of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL21$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see http://www.qt.io/terms-conditions. For further
+** information use the contact form at http://www.qt.io/contact-us.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 2.1 or version 3 as published by the Free
+** Software Foundation and appearing in the file LICENSE.LGPLv21 and
+** LICENSE.LGPLv3 included in the packaging of this file. Please review the
+** following information to ensure the GNU Lesser General Public License
+** requirements will be met: https://www.gnu.org/licenses/lgpl.html and
+** http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** As a special exception, The Qt Company gives you certain additional
+** rights. These rights are described in The Qt Company LGPL Exception
+** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include <stdio.h>
+
+#if defined(WIN32) || defined(_WIN32) || defined(__WIN32__)
+#  include <windows.h>
+
+void sleepForever()
+{
+    ::Sleep(INFINITE);
+}
+#else
+#  include <unistd.h>
+
+void sleepForever()
+{
+    ::pause();
+}
+#endif
+
+int main()
+{
+    puts("ready.");
+    fflush(stdout);
+    fprintf(stderr, "ready.\n");
+    fflush(stderr);
+
+    // sleep forever, simulating a hung application
+    sleepForever();
+    return 0;
+}