[Q] Problem with derived from streambuf class

[zaufi at sendmail dot ru]

hi list

For my project recently I develop two classes for streammed output to syslog. 
First is a syslogbuf which is derived from std::streambuf. It uses THREAD 
SPECIFIC std::string to hold string to be output to syslog. This class have 
redefined xsputn() function to append content to buffer.
Second class is a syslog_stream class (derived from ostream). It have 
syslogbuf as datamember and calls ostream constructor with pointer to it.
The problem raise when user (me :) output std::endl manipulator. Ex.:

   syslog_stream sout("ident");
  sout << "This will be printed" << std::endl;
  s.out << "This will not appear...\n";

As I investigate call sequence look like th following:
1) std::endl uses ostream::put('\n')
2) ostream::put() gets pointer to streambuf (which is set by ostreams' 
constructor to syslogbuf data member of syslog_stream)
3) ostream::put() calls NON VIRTUAL function base_streambuf::sputc() !! -- so 
there is no way to redefine it in derived classes... :(((
4) streambuf::sputc() set my syslogbuf in error state (after check pptr() for 
0) 'bcouse my class do not use pointers inherited from base_streambuf (they 
are not thread safe)

It looks like base_streambuf forces all derived classes to use buffer 
management from base_streambuf and there is no way (or I still can't see it) 
to avoid this behavior (i.e. I can't add (use) smth different than pointers 
(strings for example))...

I want to ask gurus/developers of libstdc++: Is this normal and I miss 
something important??
I'm in doubt...

regards