[Bug c++/14773] New: incorrect behavior of istringstream in gcc 3.2.3

["saunak dot chakrabarti at gs dot com" <gcc-bugzilla at gcc dot gnu dot org>]

I am using getline to loop through the lines of a file and then tokenizing with 
istringstream.  

In gcc 2.95, if a getline fetches an empty line from a file (with length=0), an 
attempt to do:
            std::istringstream s(line);
            s >> token;
            cout << token << endl;

results in token being empty, which is correct since the underlying line is 
empty.

However, in gcc 3.2.3, the same results in token retrieving its previous value 
from line.

OUTPUT of test program from gcc 2.95:
line is # $Id: router.config.PTSIPM,v 1.3 2003/11/06 15:29:47 chakrs Exp $
length is 66
token is #

line is 
length is 0
token is <---------- NOTE that token is empty here, which is correct

OUTPUT of test program from gcc 3.2.3:
line is # $Id: router.config.PTSIPM,v 1.3 2003/11/06 15:29:47 chakrs Exp $
length is 66
token is #

line is 
length is 0
token is # <---------- NOTE that token is set to '#' from the previous read

CODE SAMPLE TO REPRODUCE:
#include <iostream.h>
#include <fstream.h>
#include <sstream>

void printString(char l[])
{
   for ( int i=0;  l[i] != '\0'; i++ )
      cout << l[i];

   cout << endl;

}

void fileRd(istream &f)
{
    char       line[512];
    char       token[512];

    for (;;)
    {
        f.getline(line, sizeof(line));
        if (!f)
        {
            cerr << "Not f" << endl;
            break;
        }
        else
        {
            cout << "line is ";
            printString(line);
            cout << "length is " << strlen(line) << endl;
            std::istringstream s(line);
            s >> token;
            cout << "token is ";
            printString(token);
            cout << endl;
        }
    }
}

int main()
{
    ifstream f("router.config", ios::in);

    if (f.fail())
        return 0;

    fileRd(f);

    return 0;
}
_________________________________________________________________
The input file router.config looks like:
# $Id: router.config.PTSIPM,v 1.3 2003/11/06 15:29:47 chakrs Exp $
(empty line here)

-- 
           Summary: incorrect behavior of istringstream in gcc 3.2.3
           Product: gcc
           Version: 3.2.3
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: c++
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: saunak dot chakrabarti at gs dot com
                CC: gcc-bugs at gcc dot gnu dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14773