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pcntl_wait / pcntl_waitpid: Document the rusage parameter (fixes #861) #4917

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pcntl_wait / pcntl_waitpid: Document the rusage parameter (fixes #861) #4917

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pcntl_wait / pcntl_waitpid: Document the rusage parameter (fixes #861)
AllenJB Oct 11, 2025
fd20c6a
pcntl_wait / pcntl_waitpid: Document the rusage parameter (fixes #861…
AllenJB Oct 11, 2025
55c86d4
pcntl_wait / pcntl_waitpid: Document the rusage parameter (fixes #861…
AllenJB Oct 28, 2025
cb6baa4
pcntl_wait / pcntl_waitpid: Document the rusage parameter (fixes #861…
AllenJB Oct 28, 2025
b9cb0c2
pcntl_wait / pcntl_waitpid: Document the rusage parameter (fixes #861…
AllenJB Oct 28, 2025
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15 changes: 15 additions & 0 deletions reference/pcntl/functions/pcntl-wait.xml
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Original file line number Diff line number Diff line change
Expand Up @@ -86,6 +86,20 @@
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>resource_usage</parameter></term>
<listitem>
<para>
The <parameter>resource_usage</parameter> parameter is set to an
associative <type>array</type> containing resource usage statistics
from the child process.

This is supported either if the wait6 system call is available
(e.g. on FreeBSD), or on Linux through the raw waitid system call. For
information on the contents see <function>getrusage</function>.
</para>
</listitem>
</varlistentry>
</variablelist>
</para>
</refsect1>
Expand All @@ -105,6 +119,7 @@
<simplelist>
<member><function>pcntl_fork</function></member>
<member><function>pcntl_signal</function></member>
<member><function>pcntl_waitpid</function></member>
<member><function>pcntl_wifexited</function></member>
<member><function>pcntl_wifstopped</function></member>
<member><function>pcntl_wifsignaled</function></member>
Expand Down
8 changes: 5 additions & 3 deletions reference/pcntl/functions/pcntl-waitid.xml
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Original file line number Diff line number Diff line change
Expand Up @@ -250,11 +250,13 @@
<term><parameter>resource_usage</parameter></term>
<listitem>
<para>
The <parameter>resource_usage</parameter> parameter is set to an array
containing resource usage statistics from the child process.
The <parameter>resource_usage</parameter> parameter is set to an
associative <type>array</type> containing resource usage statistics
from the child process.

This is supported either if the wait6 system call is available
(e.g. on FreeBSD), or on Linux through the raw waitid system call.
(e.g. on FreeBSD), or on Linux through the raw waitid system call. For
information on the contents see <function>getrusage</function>.
</para>
</listitem>
</varlistentry>
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73 changes: 73 additions & 0 deletions reference/pcntl/functions/pcntl-waitpid.xml
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Original file line number Diff line number Diff line change
Expand Up @@ -130,6 +130,20 @@
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>resource_usage</parameter></term>
<listitem>
<para>
The <parameter>resource_usage</parameter> parameter is set to an
associative <type>array</type> containing resource usage statistics
from the child process.

This is supported either if the wait6 system call is available
(e.g. on FreeBSD), or on Linux through the raw waitid system call. For
information on the contents see <function>getrusage</function>.
</para>
</listitem>
</varlistentry>
</variablelist>
</para>
</refsect1>
Expand All @@ -143,12 +157,71 @@
</para>
</refsect1>

<refsect1 role="examples">
&reftitle.examples;
<para>
<example>
<title><function>pcntl_waitpid</function> example</title>
<programlisting role="php">
<![CDATA[
<?php
function checkChild(int $pid, bool $wait): void
{
$flags = ($wait ? 0 : WNOHANG);
$deadPid = pcntl_waitpid($pid, $status, $flags, $rusage);
if ($deadPid === -1) {
$errNo = pcntl_get_last_error();
$errMsg = pcntl_strerror($errNo);
print "PARENT pcntl_waitpid FAILED ({$deadPid}): {$errMsg}\n";
} elseif ($deadPid === 0) {
print "PARENT pcntl_waitpid: No exited children.\n";
} else {
print "PARENT pcntl_waitpid: Child PID {$deadPid} exited with status: "
. pcntl_wexitstatus($status) ."\n";
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The documentation for wexitstatus says:

This function is only useful if pcntl_wifexited() returned true.

So, is a wifexited call missing here? Looking more carefully at the example, it uses quite a few functions from the pcntl extension. It might make sense to include it in https://www.php.net/manual/en/pcntl.example.php instead.

var_dump($rusage);
}
}
$parentPid = getmypid();
$forkedPid = pcntl_fork();
if ($forkedPid == -1) {
die('Could not fork');
} else if ($forkedPid) {
// Parent process
print "PARENT {$parentPid} has forked {$forkedPid}\n";
print "PARENT is checking for exited children\n";
checkChild($forkedPid, false);
// Prevents children remaining as a "zombie process"
print "PARENT is waiting for a child to exit\n";
checkChild($forkedPid, true);
print "PARENT is checking for exited children\n";
checkChild($forkedPid, false);
print "PARENT is exiting\n";
} else {
// Child process
$pid = getmypid();
print "CHILD {$pid} is sleeping\n";
sleep(10);
print "CHILD is exiting\n";
exit(7);
}
]]>
</programlisting>
</example>
</para>
</refsect1>

<refsect1 role="seealso">
&reftitle.seealso;
<para>
<simplelist>
<member><function>pcntl_fork</function></member>
<member><function>pcntl_signal</function></member>
<member><function>pcntl_wait</function></member>
<member><function>pcntl_wifexited</function></member>
<member><function>pcntl_wifstopped</function></member>
<member><function>pcntl_wifsignaled</function></member>
Expand Down