[Bug c++/17611] New: ifstream could not read multiple files

[Bug c++/17611] New: ifstream could not read multiple files

[kemin dot zhou at ferring dot com]

ifstream objects could not open multiple files.
if ifstream objects have reached the end of the stream, then opening another
files requires to clear() otherwise it failed to open a second file.

example code:
ifstream IN("test1.txt");
while (IN>>line) cout << line << endl;
// at this point IN.bad() == true
IN.close();
// you must give the following command 
IN.clear();
// otherwise the following statement will fail
IN.open("test2.txt");
IN.fail() == true if the bad bit is not cleared.
====
The standard behavior is for the 
ifstream::open(string &infilename) {
  if (bad()) clear();
  ......
}

==========
reading file to the end in the first operation should not have prevented the
opening of the second file.

-- 
           Summary: ifstream could not read multiple files
           Product: gcc
           Version: 3.3.4
            Status: UNCONFIRMED
          Severity: critical
          Priority: P2
         Component: c++
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: kemin dot zhou at ferring dot com
                CC: gcc-bugs at gcc dot gnu dot org
  GCC host triplet: Linux


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=17611

[Bug libstdc++/17611] ifstream could not read multiple files

[bangerth at dealii dot org]

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
          Component|c++                         |libstdc++


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=17611

[Bug libstdc++/17611] ifstream could not read multiple files

[pcarlini at suse dot de]

------- Additional Comments From pcarlini at suse dot de  2004-09-22 15:55 -------
Not a bug, very well known, by the way, see:

  http://gcc.gnu.org/onlinedocs/libstdc++/faq/index.html#4_4_iostreamclear

The standard in force, as also clarifed by the resolution of DR22, does **not**
say that open clears the flags!

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
         Resolution|                            |INVALID


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=17611

[Bug libstdc++/17611] ifstream could not read multiple files

[kemin dot zhou at ferring dot com]

------- Additional Comments From kemin dot zhou at ferring dot com  2004-09-23 02:08 -------
Subject: Re:  ifstream could not read multiple files

pcarlini at suse dot de wrote:

>------- Additional Comments From pcarlini at suse dot de  2004-09-22 15:55 -------
>Not a bug, very well known, by the way, see:
>
>  http://gcc.gnu.org/onlinedocs/libstdc++/faq/index.html#4_4_iostreamclear
>
>The standard in force, as also clarifed by the resolution of DR22, does **not**
>say that open clears the flags!
>
>  
>
Thanks a lot.  Well, some other compilers has the ability to ability to 
open multiple files.  Maybe we should change
the standard.  I am not sure what is the benefit for leaving in the bad 
state even after a close and re.open operation.
But this is a minor thing I can live with. 

Kemin



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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=17611