Description:
------------
it only appear in the ZTS version.

use php://stdin get a line with '\n'.
use substr cutoff last char and return it.

use php://stdout print the return value, and print something else.
the return value can not be seen.


Test script:
---------------
function stdin () {
	$stdin = fopen('php://stdin','r');
	$text = fgets($stdin); // This
	fclose($stdin);
	return substr($text, 0, -1); // and This couse the problem
}

function stdout(string $data) {
	$stdout = fopen('php://stdout','a');
	$length = fwrite($stdout, $data);
	fclose($stdout);
	// $length = file_put_contents ('php://stdout', $data, FILE_APPEND);
	return $length;
}
stdout(stdin());
stdout('hello');

Expected result:
----------------
input:
12

output:
hello

Actual result:
--------------
input:
12

output:
12hello