libstdc++/5820: EOF not handled correctly on input

[jm@bourguet.org]

>Number:         5820
>Category:       libstdc++
>Synopsis:       EOF not handled correctly on input
>Confidential:   no
>Severity:       non-critical
>Priority:       low
>Responsible:    unassigned
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Sun Mar 03 11:16:01 PST 2002
>Closed-Date:
>Last-Modified:
>Originator:     jm@bourguet.org
>Release:        gcc-3.0.2
>Organization:
>Environment:
Debian Linux
>Description:
On all Unix variants I've tried, programs taking their input from a
terminal consider two CTRL-D (this key can be changed with stty, but
I'll use CTRL-D) in a row or one CTRL-D just at the beginning of a
line as an end of file indication.

With the C++ library furnished with gcc 3.0.2, executing:

#include <iostream>
#include <istream>
#include <ostream>

int main()
{
   int i;
   char c;
   
   std::cout << "Enter an integer: ";
   std::cin >> i;
   if (!std::cin) {
     std::cerr << "Unexpected read problem\n";
     return 1;
   }   
   std::cout << '\n' << "std::cin.eof()=" << std::cin.eof() << '\n';
   std::cout << "The number was: " << i << '\n';
   std::cin >> c;
   if (std::cin) {
     std::cerr << "Could read " << c << " after the number!\n";
   }   
}

on a Linux box with input and output directed to a terminal, I had to
type 4 times CTRL-D after 5 to get the expected result:

Enter an integer: 5
std::cin.eof()=1
The number was: 5

If I type "5", two or three CTRL-D and "a", I get:

Enter an integer: 5a

std::cin.eof()=0
The number was: 5
Could read a after the number!
>How-To-Repeat:
See description
>Fix:

>Release-Note:
>Audit-Trail:
>Unformatted: