libstdc++/9523: ios_base::sync_with_stdio clobbers standard streams

[peturr02@ru.is]

>Number:         9523
>Category:       libstdc++
>Synopsis:       ios_base::sync_with_stdio clobbers standard streams
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    unassigned
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Fri Jan 31 12:26:00 UTC 2003
>Closed-Date:
>Last-Modified:
>Originator:     peturr02@ru.is
>Release:        gcc-3.2.1
>Organization:
>Environment:
Red Hat Linux 8.0
>Description:
If any changes are made to the state of the standard stream objects (cin, cout etc.) before ios_base::sync_with_stdio is called, that state is lost as a result of the call.
>How-To-Repeat:
See attachment.
>Fix:

>Release-Note:
>Audit-Trail:
>Unformatted:
----gnatsweb-attachment----
Content-Type: text/plain; name="syncwstdiobug.cc"
Content-Disposition: inline; filename="syncwstdiobug.cc"

#include <iostream>

#undef NDEBUG
#include <cassert>

int main()
{
	using namespace std;

	int index = ios_base::xalloc();

	cin.iword(index) = 5;
	cout.iword(index) = 5;
	cerr.iword(index) = 5;
	clog.iword(index) = 5;
	wcin.iword(index) = 5;
	wcout.iword(index) = 5;
	wcerr.iword(index) = 5;
	wclog.iword(index) = 5;

	ios_base::sync_with_stdio(false);

	assert(cin.iword(index) == 5);
	assert(cout.iword(index) == 5);
	assert(cerr.iword(index) == 5);
	assert(clog.iword(index) == 5);
	assert(wcin.iword(index) == 5);
	assert(wcout.iword(index) == 5);
	assert(wcerr.iword(index) == 5);
	assert(wclog.iword(index) == 5);

	return 0;
}