@@ -195,11 +195,13 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
__basic_file* __ret = NULL;
if (!this->is_open() && __file)
{
- int __err;
+ int __err, __save_errno = errno;
+ // POSIX guarantees that fflush sets errno on error, but C doesn't.
errno = 0;
do
- __err = this->sync();
+ __err = fflush(__file);
while (__err && errno == EINTR);
+ errno = __save_errno;
if (!__err)
{
_M_cfile = __file;
new file mode 100644
@@ -0,0 +1,39 @@
+// 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 "" }
+
+#include <ext/stdio_filebuf.h>
+#include <cstdio>
+#include <cerrno>
+#include <testsuite_hooks.h>
+
+void
+test01()
+{
+ FILE* f = std::fopen("79820.txt", "w");
+ std::fclose(f);
+ errno = 127;
+ __gnu_cxx::stdio_filebuf<char> b(f, std::ios::out, BUFSIZ);
+ VERIFY(errno == 127); // PR libstdc++/79820
+}
+
+int
+main()
+{
+ test01();
+}
new file mode 100644
@@ -0,0 +1,53 @@
+// 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 "" }
+
+#include <ext/stdio_filebuf.h>
+#include <cstdio>
+#include <cerrno>
+#include <testsuite_hooks.h>
+
+void
+test01()
+{
+ FILE* out = std::fopen("81751.txt", "w");
+ std::fwrite("Some words.", 1, 10, out);
+
+ FILE* in1 = std::fopen("81751.txt", "r");
+ __gnu_cxx::stdio_filebuf<char> buf1(in1, std::ios::in, BUFSIZ);
+ int c = buf1.sgetc();
+ VERIFY( c == std::char_traits<char>::eof() ); // PR libstdc++/81751
+
+ std::fflush(out);
+ FILE* in2 = std::fopen("81751.txt", "r");
+ __gnu_cxx::stdio_filebuf<char> buf2(in2, std::ios::in, BUFSIZ);
+ c = buf2.sgetc();
+ VERIFY( c == 'S' );
+
+ buf1.close();
+ buf2.close();
+ std::fclose(in1);
+ std::fclose(in2);
+ std::fclose(out);
+}
+
+int
+main()
+{
+ test01();
+}
This fixes a couple of problems in __gnu_cxx::stdio_filebuf, specifically in the __basic_file::sys_open(FILE*, openmode) function it uses when constructed from an existing FILE stream. Firstly, r86756 changed __basic_file::sys_open(FILE*, openmode) to put the call to sync() before the assignment that sets _M_cfile. This means the fflush(_M_cfile) call has a null argument, and flushes all open streams. I don't think that was intentional, and we only want to flush the FILE we're constructing the streambuf with. (I think this is a regression from 3.4.3, which just flushed the one stream). Secondly, we zero errno so that we can tell if fflush sets it. We need to restore the original value to meet the promise we make at https://gcc.gnu.org/onlinedocs/libstdc++/manual/errno.html Paolo, does the this->sync() to fflush(__file) change look right? PR libstdc++/79820 PR libstdc++/81751 * config/io/basic_file_stdio.cc (sys_open(FILE*, ios_base::openmode)): Call fflush on the stream instead of calling sync() while _M_cfile is null. Restore original value of errno. * testsuite/ext/stdio_filebuf/char/79820.cc: New. * testsuite/ext/stdio_filebuf/char/81751.cc: New. Tested powerpc64le-linux, not yet committed. commit 72565d197cc91a04882a398d9d242a0581d6cc09 Author: Jonathan Wakely <jwakely@redhat.com> Date: Tue Aug 8 23:20:40 2017 +0100 PR libstdc++/81751 don't call fflush(NULL) PR libstdc++/79820 PR libstdc++/81751 * config/io/basic_file_stdio.cc (sys_open(FILE*, ios_base::openmode)): Call fflush on the stream instead of calling sync() while _M_cfile is null. Restore original value of errno. * testsuite/ext/stdio_filebuf/char/79820.cc: New. * testsuite/ext/stdio_filebuf/char/81751.cc: New.