stdin_to_stdout

[Burkhard Burow]

I'm writing a filter program which operates on data at fixed offsets
into the input. The rest of the input, a known number of bytes,
is passed to the output. 

I'm looking for a function to efficiently do:

stdin_to_stdout(n_bytes);

By efficiently I guess I mean that the input is not copied into my
programs memory, only to be written to the output and erased moments 
later. i.e. Is it posible to directly tie stdin to stdout for n bytes.

thanks

burk

e-mail please. I will forward and/or summary-post if requested.