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BIO_connect(3)                      OpenSSL                     BIO_connect(3)



NAME
       BIO_socket, BIO_bind, BIO_connect, BIO_listen, BIO_accept_ex,
       BIO_closesocket - BIO socket communication setup routines

LIBRARY
       libcrypto, -lcrypto

SYNOPSIS
        #include <openssl/bio.h>

        int BIO_socket(int domain, int socktype, int protocol, int options);
        int BIO_bind(int sock, const BIO_ADDR *addr, int options);
        int BIO_connect(int sock, const BIO_ADDR *addr, int options);
        int BIO_listen(int sock, const BIO_ADDR *addr, int options);
        int BIO_accept_ex(int accept_sock, BIO_ADDR *peer, int options);
        int BIO_closesocket(int sock);

DESCRIPTION
       BIO_socket() creates a socket in the domain domain, of type socktype
       and protocol.  Socket options are currently unused, but is present for
       future use.

       BIO_bind() binds the source address and service to a socket and may be
       useful before calling BIO_connect().  The options may include
       BIO_SOCK_REUSEADDR, which is described in "FLAGS" below.

       BIO_connect() connects sock to the address and service given by addr.
       Connection options may be zero or any combination of
       BIO_SOCK_KEEPALIVE, BIO_SOCK_NONBLOCK and BIO_SOCK_NODELAY.  The flags
       are described in "FLAGS" below.

       BIO_listen() has sock start listening on the address and service given
       by addr.  Connection options may be zero or any combination of
       BIO_SOCK_KEEPALIVE, BIO_SOCK_NONBLOCK, BIO_SOCK_NODELAY,
       BIO_SOCK_REUSEADDR and BIO_SOCK_V6_ONLY.  The flags are described in
       "FLAGS" below.

       BIO_accept_ex() waits for an incoming connections on the given socket
       accept_sock.  When it gets a connection, the address and port of the
       peer gets stored in peer if that one is non-NULL.  Accept options may
       be zero or BIO_SOCK_NONBLOCK, and is applied on the accepted socket.
       The flags are described in "FLAGS" below.

       BIO_closesocket() closes sock.

FLAGS
       BIO_SOCK_KEEPALIVE
           Enables regular sending of keep-alive messages.

       BIO_SOCK_NONBLOCK
           Sets the socket to nonblocking mode.

       BIO_SOCK_NODELAY
           Corresponds to TCP_NODELAY, and disables the Nagle algorithm.  With
           this set, any data will be sent as soon as possible instead of
           being buffered until there's enough for the socket to send out in
           one go.

       BIO_SOCK_REUSEADDR
           Try to reuse the address and port combination for a recently closed
           port.

       BIO_SOCK_V6_ONLY
           When creating an IPv6 socket, make it only listen for IPv6
           addresses and not IPv4 addresses mapped to IPv6.

       These flags are bit flags, so they are to be combined with the "|"
       operator, for example:

        BIO_connect(sock, addr, BIO_SOCK_KEEPALIVE | BIO_SOCK_NONBLOCK);

RETURN VALUES
       BIO_socket() returns the socket number on success or INVALID_SOCKET
       (-1) on error.  When an error has occurred, the OpenSSL error stack
       will hold the error data and errno has the system error.

       BIO_bind(), BIO_connect() and BIO_listen() return 1 on success or 0 on
       error.  When an error has occurred, the OpenSSL error stack will hold
       the error data and errno has the system error.

       BIO_accept_ex() returns the accepted socket on success or
       INVALID_SOCKET (-1) on error.  When an error has occurred, the OpenSSL
       error stack will hold the error data and errno has the system error.

SEE ALSO
       BIO_ADDR(3)

HISTORY
       BIO_gethostname(), BIO_get_port(), BIO_get_host_ip(),
       BIO_get_accept_socket() and BIO_accept() were deprecated in OpenSSL
       1.1.0.  Use the functions described above instead.

COPYRIGHT
       Copyright 2016-2020 The OpenSSL Project Authors. All Rights Reserved.

       Licensed under the Apache License 2.0 (the "License").  You may not use
       this file except in compliance with the License.  You can obtain a copy
       in the file LICENSE in the source distribution or at
       <https://www.openssl.org/source/license.html>.



3.0.12                            2023-05-07                    BIO_connect(3)