Re: [Boost-users] [iostreams] Assertion in detail/optional.hpp, line 54

18 Nov 2005


      Daniel Lidström wrote:
...
Hello!
when compiled in debug mode, the following program causes an exception
in the file p:\boost_1_33_0\include\boost-1_33\boost\iostreams\detail\
optional.hpp, line 54 (I'm using VC 7.1.3088, Windows XP):
#include <iostream>
#include            // sink
#include              // stream
using namespace std;
<snip>
...
template<int id>
class my_sink : public boost::iostreams::sink
{
public:
std::streamsize write(const char* s, std::streamsize n)
   {
      gpOutput->print(id, s);
      std::streamsize sz = 0;
      for( const char* p=s; *p; ++p ) sz++;
      return sz;
   }
};
typedef boost::iostreams::stream > output;
int main()
{
   gpOutput = new Output;
output stream;
stream << "Daniel" << endl;
Here's the problem: you're writing to a stream without opening it. Try:

     output stream;
     stream.open(my_sink());
     stream << "Daniel" << endl;
...
return 0;
}
...
Hälsningar,
Daniel
-- 
Jonathan Turkanis
www.kangaroologic.com