note 77603 added to ref.pcntl

(PHP 5.2.4) This is an example of multithreading keeping different connections to a mysql database: when children exit they close the connection and others can't use it any more generating problems. In this example I used variable variables to make a different connection per each child. This scripts loops forever with one mother detached from the terminal and five children 'named' from 1 to 5. When one children sees it's name in the database (one table 'test.tb' with only one field 'test') he lets himself die. To kill children insert their value in the db. The mother suicides only when all children are dead. What a sad but interesting story... $npid = pcntl_fork(); // DETACH FROM TERMINAL AND BE REAPED BY INIT if ($npid==-1) die("Error: impossible to pcntl_fork()\n"); else if ($npid) exit(0); // THE GRANPA DIES else // MOTHER GOES ON TO MAKE CHILDREN { $children = 5; for ($i=1; $i<=$children; $i++) { $pid = pcntl_fork(); if ($pid==-1) die("Error: impossible to pcntl_fork()\n"); else if ($pid) { $pid_arr[$i] = $pid; } if (!$pid) // CHILDREN { global $vconn; $vconn = "vconn$i"; global $$vconn; $$vconn = @mysql_connect("mydbhost","mydbuser","mydbpwd"); if (!($$vconn)) echo mysql_error(); if (!($$vconn)) exit; while (1) { $query = "SELECT test FROM test.tb"; $rs = mysql_query($query,$$vconn); $rw = mysql_fetch_row($rs); if ($rw[0]==$i) exit; else { echo "Database is $rw[0] and I am $i, it's not my time, I will wait....\n"; sleep(1); } } } } foreach ($pid_arr as $pid) { // we are the parent and we wait for all children to die pcntl_waitpid($pid, $status); } echo "All my children died, I will suicide...\n"; exit(); } ---- Server IP: 80.241.173.254 Probable Submitter: 84.220.187.18 ---- Manual Page -- http://www.php.net/manual/en/ref.pcntl.php Edit -- https://master.php.net/note/edit/77603 Del: integrated -- https://master.php.net/note/delete/77603/integrated Del: useless -- https://master.php.net/note/delete/77603/useless Del: bad code -- https://master.php.net/note/delete/77603/bad+code Del: spam -- https://master.php.net/note/delete/77603/spam Del: non-english -- https://master.php.net/note/delete/77603/non-english Del: in docs -- https://master.php.net/note/delete/77603/in+docs Del: other reasons-- https://master.php.net/note/delete/77603 Reject -- https://master.php.net/note/reject/77603 Search -- https://master.php.net/manage/user-notes.php