Simple reading of binary data

[Matt]

I'm having real trouble reading binary data from a file. I've 
been trying to use the functions from std.stdio, but keep running 
into problems. When I try;

byte b;
auto file = new File( "some binary file" );
file.readf( "%d", &b );
I get "Unexpected '€' when converting from type 
LockingTextReader to type int"
What functions do I use to read individual bytes, shorts, ints, 
longs and the like?