https://forge.codesys.com/forge/talk/Engineering/thread/c089073e84/2020-02-27T13:57:35.307000ZRecent posts to SysSocket23 and SysSockRecv2020-02-27T13:57:35.307000Z2020-02-27T13:57:35.307000Zdiego.berninihttps://forge.codesys.com/u/diego-bernini/https://forge.codesys.com47d76f5868a421b945e1f0af5b1f2dca07850d39

<div class="markdown_content"><p>Hello,<br/> we are quite new to CodeSys 3.5, while we are quite experienced with CodeSys 2.</p> <p>In CodeSys 2 for managing incoming TCP connections we used the 'SysLibSocket.lib' library, that seems that it been ported in CodeSys 3.5 as 'SysSocket23'.</p> <p>The fact is that we noticed a strange behavior of the new Librarys w.r.t. the following call:</p> <p>m_BytesReceived:= SysSockRecv( m_Socket, ADR(m_ReceiveBuffer), SIZEOF(m_ReceiveBuffer), 0);</p> <p>In CodeSys 2, with 'SysLibSocket.lib', m_BytesReceived is valued to 0 when the socket is closed by the client, -1 only if the socket is active and no characters have been sent by the client.</p> <p>In CodeSys 3, with 'SysSocket23' we noticed that m_BytesReceived is -1 in both cases: if the socket is active and no data have been sent, but also if the socket has been closed by the client.</p> <p>How can we detect if the client has closed the socket with CodeSys 3 and 'SysSocket23'?</p> <p>Many thanks,<br/> Diego</p></div>