Re: closing stream before opening sets fail bit

[brent verner <brent at rcfile dot org>]

on Sat, Jun 17, 2000 at 04:38:47PM -0700, Rob Willis typed aloud:
| 
| 
| Found this quirky behavior. Is this the correct behavior? Basically, calling
| close() before opening the ofstream causes the fail bit to be
| set. I can live with that... But then, the open command succeeds and the
| fail bit is still set!!  And of course the write fails.


  27.8.1.3

  basic_filebuf<charT,traits>* open(
                      const char* s,
                      ios_base::openmode mode);

  Effects: If is_open() != false, returns a null pointer. Otherwise, 
           initializes the filebuf as required.

Now, 'as required' is a bit vague :), but that implies to me that
after a successful open(), the returned basic_filebuf should be
in a normal, operational state... which means we need to explicitly
clear() the [io]fstream inside of open(), which will (re)set the
failbit if there is any _real_ failure in rdbuf()->open(). If this 
is sane, the patch below may be applied. If it breaks 
Things I Don't Know About, please let me know.

Cheers.
  Brent

*** /usr/local/cvs/libstdc++-v3/bits/std_fstream.h	Mon May  1 20:27:21 2000
--- std_fstream.h	Sun Jun 18 15:55:17 2000
*************** namespace std {
*** 289,297 ****
        void 
        open(const char* __s, 
  	   ios_base::openmode __mode = ios_base::out | ios_base::trunc)
!       { 
  	if (!rdbuf()->open(__s, __mode | ios_base::out))
! 	  this->setstate (ios_base::failbit); 
        }
  
        void 
--- 289,298 ----
        void 
        open(const char* __s, 
  	   ios_base::openmode __mode = ios_base::out | ios_base::trunc)
!       {
! 	this->clear();
  	if (!rdbuf()->open(__s, __mode | ios_base::out))
! 	  this->setstate(ios_base::failbit); 
        }
  
        void 

-- 
Damon Brent Verner
Cracker JackŪ Certified Professional
brent@rcfile.org, brent@linux1.org