TCP Connect error 115 Operation in Progress What is the Cause?

Question

My application creats a TCP connection, This is working normaly. But in one network server has many IP say

• 174.X.X.X
• 54.x.x.x like this

Answer 1

This seems to be the behaviour of connect():

If the connection cannot be established immediately and O_NONBLOCK is set for the file descriptor for the socket, connect() shall fail and set errno to [EINPROGRESS], but the connection request shall not be aborted, and the connection shall be established asynchronously. Subsequent calls to connect() for the same socket, before the connection is established, shall fail and set errno to [EALREADY].