Fixed error with push/pop position, works fine now

binary_archive/binary_archive.hpp

@@ -28,7 +28,8 @@ namespace cereal
       void pushPosition( size_t size )
       {
         itsPositionStack.push( itsStream.tellp() );
-        itsStream.write( 0, size );
+        for(size_t i = 0; i < size; ++i)
+          itsStream.rdbuf()->sputc('\0'); // char doesn't matter, but null-term is zero
       }
 
       //! Pops the most recently pushed position onto the archive, going to the end

test.cpp

@@ -205,9 +205,15 @@ int main()
     std::cout << std::endl;
   }
 
-  std::ostringstream os;
+  std::ofstream os("test.txt");
+  cereal::BinaryOutputArchive archive(os);
   std::cout << "Testing:" << std::endl;
-  //os.write(, 5);
+
+  archive & uint8_t();
+  archive & uint16_t(3);
+  //os.write("\0", 1);
+
+
 
   return 0;
 }