Specific Design Question

[3hM2Nwbp]

I'm designing a user-friendly interface for working with modern OpenGL, and I have a few concerns regarding some areas.

1) Vertex Buffer Objects - would it be safe to assume that the data will always be in a format that has 1 meaning, and 1 meaning only? What I was thinking about doing was hiding the attribute pointers inside the class that wraps the concept of a VBO. However doing so would prevent using the same VBO in a different context without copying it (expensive). I can't for the life of me think of a time when VBO data could be re-used and re-interpreted in a different way, with different attribute pointers. Can you? A small mock-up below:

#include <array>
#include <cstdint>
#include <list>
#include <string>

/// Basically manages various platform-specific configurations
#include "Platform.hpp"

namespace detail
{
  struct AttributePointerBase
  {
    // Fiddle with state and call glVertexAttrib*Pointer
    virtual void bind(GLuint programHandle) = 0;
    virtual void unbind() = 0;
  }
  struct AttributePointer /* : public AttributePointerBase */;
  struct AttributeIPointer /* : public AttributePointerBase */;
  struct AttributeLPointer /* : public AttributePointerBase */;
}

class VertexBuffer
{
  std::list<AttributePointerBase> attributes;

  public:

    void setAttributePointer(/* ... */);
    void setAttributeIPointer(/* ... */);
    void setAttributeLPointer(/* ... */);
    // ...
    void bind(GLuint programHandle)
    {
      for(AttributePointerBase& attr : attributes)
      {
        attr.bind(programHandle);
      }
    }
    // ...
};

2) http://www.opengl.org/sdk/docs/man4/xhtml/glUseProgram.xml#Errors
"GL_INVALID_OPERATION is generated if program could not be made part of current state."

WHAT! Ambiguous anyone? How am I to report to the user a call to the implementation failed going on that ambiguous failure condition. Is there any more detailed documentation available?

3) I'll re-use this thread if / when a new issue arises.

Thanks in advance for any input!

* Current progress can be tracked @ https://bitbucket.org/DarkHeart/opengl
The license is the most clever part of the whole project.