Interrupting the TCP handshake with PHP's fsockopen()?

Take for example:

fsockopen(tcp:\\example.com, 80, $errno, $errstr, 5)

My friend has just informed me that PHP will always wait for the TCP handshake to be complete开发者_如何学编程d before closing the socket. However, I find it difficult to believe that PHP can't interrupt the handshake.

Is it possible? If so, how?

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No, It is not possible.