Style Question

I have a stylistic question.

I have an application where I need a queue of buffers whose size changes
relatively often. I was doing it with a "char *" with separate Size and
MaxSize members, but it seemed like a great candidate for a
std::vector<char>. After the size changes, I fill it immediately, so the
zero filling that vector::resize does is useless to me, and it costs a
fair amount.

So, I derived a class from std::vector<char>, and overrode resize, using
knowledge of the VC++ STL implementation:

  class ByteVector
      : public std::vector<char>
  {
      ...
      void resize( size_t newSize, char init = -1 )
      {
          if( (init == -1) && (_Myfirst + newSize <= _Myend) )
              _Mylast = _Myfirst + newSize;
          else
              std::vector<char>::resize( newSize, init );
      }
  };

This solves my problem neatly, but is this considered very bad form? It's
certainly true that this won't work with another STL implementation. Would
you fire a programmer that did this to you?
--
Tim Roberts, timr@probo.com
Providenza & Boekelheide, Inc.