Re: libstdc++/5292: Assumes streambuf::overflow returns character put

Re: libstdc++/5292: Assumes streambuf::overflow returns character put

[Paolo Carlini]

The following reply was made to PR libstdc++/5292; it has been noted by GNATS.

From: Paolo Carlini <pcarlini@unitus.it>
To: gcc-gnats@gcc.gnu.org, gcc-prs@gcc.gnu.org,
	vaniwaar@ca.metsci.com, ron@vaniwaarden.org,
	gcc-bugs@gcc.gnu.org, paolo@gcc.gnu.org
Cc:  
Subject: Re: libstdc++/5292: Assumes streambuf::overflow returns character put
Date: Fri, 18 Jan 2002 10:29:59 +0100

 Correction: this PR is *not* a perfect duplicate of 5181 and 3272 (i.e., 
 the original patch for 3272 does not fix it by itself).
 The remaining considerations in the audit trail are still correct, anyway.
 
 Cheers, Paolo.
 
 http://gcc.gnu.org/cgi-bin/gnatsweb.pl?cmd=view%20audit-trail&database=gcc&pr=5292 
 
 

Re: libstdc++/5292: Assumes streambuf::overflow returns character put

[bkoz]

Synopsis: Assumes streambuf::overflow returns character put

State-Changed-From-To: feedback->closed
State-Changed-By: bkoz
State-Changed-When: Tue Apr  2 18:29:57 2002
State-Changed-Why:
    This is not a bug. 
    27.5.2.2.5 - Put area [lib.streambuf.pub.put]
    streambuf::sputc
    
    returns: 
    if no write, overflow(traits::to_int_type(c))
    else traits::to_int_type(c)
    
    You'll notice that the libstdc++-v3 implementation does this.
    
    27.5.2.4.5 - Put area [lib.streambuf.virt.put]
    overflow always returns c on success, unless c == EOF, in which it
    returns not_eof().
    
    Overflow never returns EOF on success, so your change is not
    necessary, and indeed, would be non-conforming.
    
    Furthermore, your testcase appears to work with current gcc-3.1 sources.

http://gcc.gnu.org/cgi-bin/gnatsweb.pl?cmd=view%20audit-trail&database=gcc&pr=5292