Read Line From Pipe

[inbox_pub earthlink net]

I have written an application that I compile with:
`pkg-config libgnomedbmm-3.0 --cflags --libs`

The test that I am using right now is this:
-Make selections from radio buttons and check boxes, and
  when the Accept button is clicked, write information to the pipe.
-The pipes simply loop and are read in by the Gtkmm read_line().
-Lets say that the information is "button1\nbutton2\nbutton3\n"
-I know that the three lines are getting to the Gtkmm signal to
 call my read pipe routine.
-I display in a Gtkmm window what is read with the read_line().
-When I click the Accept button:
 First: "button1\n"
 Second:  "button2\nbutton3\nbutton1\nbutton2\n"
 Third:  "button3\nbutton1\nbutton2\n"

In my second test, I individually write the information for each
button with a sleep(1) between them. I get:
First: "button1\n"
Second: "button2\nbutton3\nbutton1\n"
Third: "button2\nbutton3\nbutton1\n"

I flush the write pipe after every write. All pipes are configured
non-blocking.
My read function is basically that shown in the Gtkmm MonitorIO chapter.

Is this normal behavior?
Or is there something going on that I don't know?

Thank you.