I have found the following template to be quite useful for file IO. Just thought I'd post it.

BTW  if it is compiled with the -D option the it gets the this error

data.d(14): Error: static if conditional cannot be at global scope

from doc:
"StaticIfConditions cannot appear at module scope. They can appear in class, template, struct, union, or function scope"

---------------------------
/**
 * A template providing raw access to a file stream.
 * Authors:  Benjamin Shropshire
 *           shro_8822@uidaho@edu  (remove '_')
 * Date:     12/30/2005
 * Version:  1.0
 */
template Data(T)
{
    // Make sure objects aren't used
    // (they wouldn't work right)
  static assert(!is(T:Object));

    // Warn if used with a pointer
    //(they most likely aren't what is wanted)
  static if(is(T:void*))
  {
    pragma(msg,
    "Data!(T) used with a pointer type, is this intended?\n");
  }

    /// Read and ignore the right amount of data from the stream.
  void Discard(Stream ins)
  {
    T ret;
    ins.readExact(&ret, T.sizeof);
    return;
  }

    /// Read and return one of the given type from the stream.
  T Read(Stream ins)
  {
    T ret;
    ins.readExact(&ret, T.sizeof);
    return ret;
  }

    /// Read and return i of the given type from the stream.
  T[] Read(Stream ins, int i)
  {
    T[] ret = new T[i];
    ins.readExact(ret.ptr, T.sizeof*i);
    return ret;
  }

    /// Write enough data for one of the given type to the stream
  void Write(Stream ins)
  {
    T dat;
    ins.writeExact(&dat, T.sizeof);
  }

    /// Write all of dat's elements to the stream.
  void Write(Stream ins, T[] dat)
  {
    ins.writeExact(dat.ptr, T.sizeof*dat.length);
  }

    /// Write dat to the stream.
  void Write(Stream ins, T dat)
  {
    ins.writeExact(dat, T.sizeof);
  }
}