<explain>
This case is a very simple interaction between the TCP client side and the TCP server side
<?php
$sock = socket_create(AF_INET, SOCK_STREAM, getprotobyname('tcp'));
socket_bind($sock, '127.0.0.1',5000);
socket_listen($sock,1);
$clnt_sock = socket_accept($sock); $st = "hello world ^_^";
socket_write($clnt_sock, $st,strlen($st));
socket_close($clnt_sock);
socket_close($sock);
?>
<?php
$clnt_sock = socket_create(AF_INET, SOCK_STREAM, getprotobyname('tcp'));
socket_connect($clnt_sock, '127.0.0.1', 5000);
$ret= socket_read($clnt_sock, 1024);
print "from simple-tcp-server:".$ret.PHP_EOL;
socket_close($clnt_sock);
?>
<fruit>
from simple-tcp-server:hello world ^_^