Asynchronous read not work

[fatalerror8787]

I'm new in C++.

My embeded sensor send character like this
Roll=5.413759 Pitch=16.861174 Yaw=175.750381
Acceleration: X=-3294 Y=-44 Z=2463
Gyroscope: X=-1 Y=0 Z=-1
Magnetic: X=45 Y=23 Z=-65
END

Roll=6.413759 Pitch=17.861174 Yaw=176.750381
Acceleration: X=-3294 Y=-44 Z=2463
Gyroscope: X=-1 Y=0 Z=-1
Magnetic: X=45 Y=23 Z=-65
END

I use example 1, asio::read, is OK.
I change to example 3 or 4, asychronous read, the console is always blank. It could input, but receive noting.
Any suggestion, thanks in advance.

[fedetft]

What's in your receive callback?