how get the output from process opend by popen in php?

Question

file a.php:

<?php
echo "abcdef";
?>

file b.php:

<?php
$h=popen('php a.php',r);
pclose($h);
?>

question:

I can't see the echo result on console; why and how to see it?

I don't want to do it in file b.php like:echo stream_get_contents($h);

Answer 1

Check the second example in the documentation on popen, it shows exactly how to do that:

<?php
error_reporting(E_ALL);

/* Add redirection so we can get stderr. */
$handle = popen('/path/to/executable 2>&1', 'r');
echo "'$handle'; " . gettype($handle) . "
";
$read = fread($handle, 2096);
echo $read;
pclose($handle);

This snippet reads from stderr. Remove the pipe to read from stdout.