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67 lines
2.1 KiB

2017-07-18 Jonathan Wakely <jwakely@redhat.com>
PR libstdc++/81395
* include/bits/fstream.tcc (basic_filebuf::xsgetn): Don't set buffer
pointers for write mode after reading.
* testsuite/27_io/basic_filebuf/sgetn/char/81395.cc: New.
--- libstdc++-v3/include/bits/fstream.tcc (revision 254017)
+++ libstdc++-v3/include/bits/fstream.tcc (revision 254018)
@@ -699,7 +699,7 @@
if (__n == 0)
{
- _M_set_buffer(0);
+ // Set _M_reading. Buffer is already in initial 'read' mode.
_M_reading = true;
}
else if (__len == 0)
--- libstdc++-v3/testsuite/27_io/basic_filebuf/sgetn/char/81395.cc (nonexistent)
+++ libstdc++-v3/testsuite/27_io/basic_filebuf/sgetn/char/81395.cc (revision 254018)
@@ -0,0 +1,46 @@
+// Copyright (C) 2017 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-require-fileio "" }
+
+// PR libstdc++/81395
+
+#include <fstream>
+#include <cstring> // for std::memset
+#include <cstdio> // For BUFSIZ
+
+using std::memset;
+
+int main()
+{
+ {
+ std::filebuf fb;
+ fb.open("test.txt", std::ios::out);
+ char data[BUFSIZ];
+ memset(data, 'A', sizeof(data));
+ fb.sputn(data, sizeof(data));
+ }
+
+ std::filebuf fb;
+ fb.open("test.txt", std::ios::in|std::ios::out);
+ char buf[BUFSIZ];
+ memset(buf, 0, sizeof(buf));
+ fb.sgetn(buf, sizeof(buf));
+ // Switch from reading to writing without seeking first:
+ fb.sputn("B", 1);
+ fb.pubsync();
+}