# Socket Open and Close

    /*
    **	(c) COPYRIGHT MIT 1995.
    **	Please first read the full copyright statement in the file COPYRIGH.
    */

The Socket Open and Close methods knows how to establish a BSD socket TCP connection and is part of the Transport interface.

This module is implemented by HTTCP.c, and it is a part of the W3C Sample Code Library.

    #ifndef HTTCP_H
    #define HTTCP_H
    #include "HTReq.h"
    #include "HTNet.h"

## Active Connection Establishment

This makes an active `connect` to the specified host. An HTNet Object is parsed in order to handle errors and other stuff. The default port might be overwritten by any port indication in the URL specified as `<host>:<port>` If it is a multihomed host (a host having multiple IP-addresses with the same host name) then `HTDoConnect()` measures the time it takes to connect and updates the calculated weights in the DNS object.

    extern int HTDoConnect (HTNet * net, char * url, u_short default_port);

## Passive Connection Establishment

This function makes an `accept` on a port. The net must contain a valid socket to accept on. If accept is OK then we duplicate the net object and assign the accepted socket to the newly created net object. The original Net object will keep accepting connections on the original socket, for example port 80 in the case of HTTP. The newly created Net object will be freed when the protocol module has finished. If the accepted net object pointer points to the net object itself, that is - the same object all along - then we reuse the same Net obejct; closes the original socket and replaces it wik the accepted one. This is a quick way of accepting a single connection.

    extern int HTDoAccept (HTNet * net, HTNet ** accepted);

## Listen on a Socket

Listens on the specified port. Passing port `0` means that we don't care and a temporary one will be assigned. If `master`==INVSOC then we listen on all local interfaces (using a wildcard). If `INVSOC` is not `NULL` then use this as the local interface. `backlog` is the number of connections that can be queued on the socket - you can use `HT_BACKLOG` for a platform dependent value (typically 5 on BSD and 32 on SVR4). Returns `HT_ERROR` or `HT_OK`.

    extern int HTDoListen (HTNet * net, u_short port, SOCKET master, int backlog);

## Closing a socket

Closes a socket

    extern int HTDoClose (HTNet * net);

    #endif   /* HTTCP_H */