From: "Michael N. Filippov" <michael AT idisys DOT iae DOT nsk DOT su>
Newsgroups: gnu.g++.help,gnu.gcc.help,comp.os.msdos.djgpp
Subject: ostringstream / not enough memory
Date: 31 Oct 2001 11:32:21 GMT
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To: djgpp AT delorie DOT com
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Reply-To: djgpp AT delorie DOT com

Hello !

Can somebody explain why ostringstream does not throw in this example
but just stops growing. Maybe it is my local installation problem (hardly 
but anyway - I use DJGPP 2.03, GCC 3.02) so if you can recreate not under DOS
it would help too. Code is very simple:

#include <iostream>
#include <sstream>

using namespace std;

int main(void)
{
  char* buffer(0);
  const size_t buffer_length(1 * 1000 * 1000);
  try {
    buffer = new char[buffer_length + 1]; // + 1 for terminating '\0'
    memset(buffer, 'A', buffer_length);
    buffer[buffer_length] = 0;
    //
    ostringstream oss;
    string::size_type curr_oss_str_length;
    string::size_type prev_oss_str_length(0);
    while (true) {
      oss << buffer;
      curr_oss_str_length = oss.str().length();
      if (curr_oss_str_length != prev_oss_str_length + buffer_length) {
        cerr << "appended " << curr_oss_str_length - prev_oss_str_length
             << " instead of " << buffer_length << endl
             << "entire length " << curr_oss_str_length << endl;
       break;
      }
      prev_oss_str_length = curr_oss_str_length;
    }
  } catch (...) {
    cerr << "catch (...)" << endl;
  }
  delete buffer;
  return 0;
}

I see that if there is not enough memory string just stops growing.
BTW - same code with my previous configuration (GCC 2.95.2, same <sstream>)
caused SIGABRT from throw_helper (it couldn't find exception handler 
I suppose)

I would expect that in this example/ code should throw bad_alloc (like if 
using not ostringstream. but just std::string of std::vector).

What is wrong ?

Thanks in advance,
Michael