PHP: Hypertext Preprocessor (original) (raw)

pcntl_waitpid

(PHP 4 >= 4.1.0, PHP 5, PHP 7, PHP 8)

pcntl_waitpid — Waits on or returns the status of a forked child

Description

pcntl_waitpid(
int $process_id,
int &$status,
int $flags = 0,
array &$resource_usage = []
): int

If a child as requested by process_id has already exited by the time of the call (a so-called "zombie" process), the function returns immediately. Any system resources used by the child are freed. Please see your system's waitpid(2) man page for specific details as to how waitpid works on your system.

Parameters

process_id

The value of process_id can be one of the following:

possible values for process_id

< -1	wait for any child process whose process group ID is equal to the absolute value of process_id.
-1	wait for any child process; this is the same behaviour that the pcntl_wait() function exhibits.
0	wait for any child process whose process group ID is equal to that of the calling process.
> 0	wait for the child whose process ID is equal to the value ofprocess_id.

Note:

Specifying -1 as the process_id is equivalent to the functionality pcntl_wait() provides (minus flags).

status

pcntl_waitpid() will store status information in the status parameter which can be evaluated using the following functions:pcntl_wifexited(),pcntl_wifstopped(),pcntl_wifsignaled(),pcntl_wexitstatus(),pcntl_wtermsig() andpcntl_wstopsig().

flags

The value of flags is the value of zero or more of the following two global constantsOR'ed together:

possible values for flags

WNOHANG	return immediately if no child has exited.
WUNTRACED	return for children which are stopped, and whose status has not been reported.

Return Values

pcntl_waitpid() returns the process ID of the child which exited, -1 on error or zero if [WNOHANG](pcntl.constants.php#constant.wnohang) was used and no child was available

Found A Problem?

saguto dot l7cc at gmail dot com ¶

17 years ago

please note, if you using configure option --enable-sigchild(Enable PHP's own SIGCHLD handler) when complie php(under linux 2.6.18-53.1.13.el5.centos.plus and php 5.2.5 as I know), pcntl_waitpid and pcntl_wait in php script would never return the child pid, because the build in handle get it first.

fx4084 at gmail dot com ¶

10 years ago

`<?php
$childs = array();// Fork some process.
for($i = 0; i<10;i < 10; i<10;i++) {
$pid = pcntl_fork();
if($pid == -1)
die('Could not fork');

if (

$pid) {
echo "parent \n"; childs[]=childs[] = childs[]=pid;
} else {
// Sleep i+1(s).Thechildprocesscangetthisparameters(i+1 (s). The child process can get this parameters(i+1(s).Thechildprocesscangetthisparameters(i).
sleep($i+1);// The child process needed to end the loop.
exit();
}
}

while(

count($childs) > 0) {
foreach($childs as key=>key => key=>pid) { res=pcntlwaitpid(res = pcntl_waitpid(res=pcntlwaitpid(pid, $status, WNOHANG);// If the process has already exited
if($res == -1 || $res > 0)
unset($childs[$key]);
}sleep(1);
}
?>`

renmengyang567 at gmail dot com ¶

6 years ago

<?phpdeclare(ticks = 1); function zp_handler($signal) { <math xmlns="http://www.w3.org/1998/Math/MathML"><semantics><mrow><mi>i</mi><mi>d</mi><mo>=</mo><mi>p</mi><mi>c</mi><mi>n</mi><mi>t</mi><msub><mi>l</mi><mi>w</mi></msub><mi>a</mi><mi>i</mi><mi>t</mi><mi>p</mi><mi>i</mi><mi>d</mi><mo stretchy="false">(</mo><mo>−</mo><mn>1</mn><mo separator="true">,</mo></mrow><annotation encoding="application/x-tex">id = pcntl_waitpid(-1, </annotation></semantics></math>id=pcntlwaitpid(−1,status, WNOHANG); if (pcntl_wifexited($status)) { printf("Removed Chlid id: %d \n",$id); printf("Chlid status: %d \n",pcntl_wexitstatus($status)); } }//pcntl_signal_dispatch(); pcntl_signal(SIGCHLD, "zp_handler"); //pcntl_signal_dispatch(); //$pid = pcntl_fork(); if ($pid == 0) { print "#1 Hi, I'm child process".PHP_EOL; sleep(3); return 10; } else { print "#1parent process id:".$pid.PHP_EOL; $pid = pcntl_fork(); if ($pid == 0) { print "#2 Hi, I'm child process".PHP_EOL; sleep(10); exit(20); } else { print "#2parent process id:".$pid.PHP_EOL; for ($i=0; <math xmlns="http://www.w3.org/1998/Math/MathML"><semantics><mrow><mi>i</mi><mo><</mo><mn>10</mn><mo separator="true">;</mo></mrow><annotation encoding="application/x-tex">i <10 ; </annotation></semantics></math>i<10;i++) { print "wait..".PHP_EOL; sleep(10); } } } ?>

PHP: Hypertext Preprocessor (original) (raw)

pcntl_waitpid

Description

Parameters

Return Values

See Also

Found A Problem?