string -> pointer question

[Angus Leeming]

When the loading status of a graphics file changes, I need to inform LyX. I 
do this with:

LyXFunc::dispatch(LFUN_GRAPHICS_CHANGED_STATE, argument);

where argument is a list of insets as a space-separated string.
I split the string up and convert each substring back to a pointer with:

bool isStrPtr(string const & str)
{
        return isStrUnsignedInt(str);
}


void * strToPtr(string const & str)
{
        return (void *)strToUnsignedInt(str);
}

Is there a better way?
Angus