Format double in decimal notation without trailing zeros after the decimal point

[akaDemik via Digitalmars-d-learn]

The task seemed very simple. But I'm stuck.
I want to:
  1234567890123.0 to "1234567890123"
  1.23 to "1.23"
  1.234567 to "1.2346".
With format string "%.4f" i get "1.2300" for 1.23.
With "%g" i get "1.23456789e+12" for "1234567890123.0".
I can not believe that it is not implemented. What did I miss?