winsock "invalid argument" error on listen

Question

I was trying to make a simple client - server communication application, but I've come across a problem - I get error 10022 ( invalid argument ) on listen.

WSADATA wsaData;
int iResult;
sockaddr_in addr;
SOCKET sock, client;
addr.sin_family = AF_INET;
addr.sin_port = htons( 25565 );
addr.sin_addr.S_un.S_addr = inet_addr( "127.0.0.1" );

iResult = WSAStartup( MAKEWORD( 2, 2 ), &wsaData );

if( iResult )
{
    std::cout << ( WSAGetLastError( ) );
    _getch( );
}

sock = socket( AF_INET, SOCK_STREAM, IPPROTO_TCP );

if( sock == INVALID_SOCKET )
{
    std::cout << ( WSAGetLastError( ) );
    _getch( );
}

iResult = listen( sock, SOMAXCONN );

if( iResult )
{
    std::cout << ( WSAGetLastError( ) );
    _getch( );
}

score 3 · Accepted Answer · answered Oct 28 '18 at 19:27

Before you listen, you need to bind the socket to the port that will be listened on.

It looks like you have already built the address structure containing the information necessary to bind, so call bind(sock, &addr, sizeof(addr)) and perform appropriate error checking before the call to listen.

Documentation for bind

score 2 · Answer 2 · answered Oct 28 '18 at 21:13

2

The answer is in the listen() documentation:

WSAEINVAL

The socket has not been bound with bind.

You need to bind() the socket before you can listen() on it.

answered Oct 28 '18 at 21:13

Remy Lebeau

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winsock "invalid argument" error on listen

2 Answers2