fstream behaviour error / wrong installation ?

[Stephane MILLET <stephane dot millet at dassault-aviation dot fr>]

Hello,

Hope I'm on the right list for this kind of problem, if not sorry.
My problem: i wrote the following very simple program, but the output is 
wrong, if you have any idea, is it my installation or something i don't 
understand ?

#include <iostream>
#include <sstream>
#include <string>
#include <fstream>
#include <list>

using namespace std;

main(int argn, char**argc) {

 string sbuff = "123456789012345678901234567890";

 ofstream toto;
 toto.open("toto",ios::out);
 toto.write( sbuff.c_str() , 25);
 toto.close();
 toto.open("toto",ios::ate);
 toto.seekp(20,ios::beg);
 toto.write( sbuff.c_str() , 25);
 toto.close();

}

The expected behaviour was :
   * open a file, write 25 bytes, close it, re-open for adding, set 
position 20 from beginning, write 25 more bytes
But the actual output is :

$ od -a toto
0000000 nul nul nul nul nul nul nul nul nul nul nul nul nul nul nul nul
0000020 nul nul nul nul   1   2   3   4   5   6   7   8   9   0   1   2
0000040   3   4   5   6   7   8   9   0   1   2   3   4   5

I compiled and ran the code as follow :

$ g++ toto.cc
$ ldd ./a.out
       libstdc++.so.5 => /usr/lib/libstdc++.so.5 (0x007e2000)
       libm.so.6 => /lib/tls/libm.so.6 (0x00516000)
       libgcc_s.so.1 => /lib/libgcc_s.so.1 (0x007d8000)
       libc.so.6 => /lib/tls/libc.so.6 (0x003db000)
       /lib/ld-linux.so.2 => /lib/ld-linux.so.2 (0x003c3000)

$ uname -a
Linux pingu 2.4.22-1.2115.nptlsmp #1 SMP Wed Oct 29 15:30:09 EST 2003 
i686 i686 i386 GNU/Linux

$ g++ --version
g++ (GCC) 3.3.2 20031022 (Red Hat Linux 3.3.2-1)

Thank you
Regards
Stephane MILLET