Actually I shutdown the server process, to which my socket was connected. Even so, the syswrite returned true, i.e the write succeeded.
Here is the background: my test script opens a socket to the server and sleeps for 10 seconds, followed by a syswrite on the socket. During this 10 second window, I shutdown the server process (which takes around 3 seconds). I noticed even when the server process is not there anymore, the syswrite succeeds.