<?php
$spl = new SplFileObject('php://temp', 'r');
$fh = fopen('php://temp', 'r');
var_export([
'SplFileObject::fputcsv result on failure' => $spl->fputcsv(['foo', 'bar']),
'SplFileObject::fwrite result on failure' => $spl->fwrite('foo'),
'fputcsv result on failure' => fputcsv($fh, ['foo', 'bar']),
'fwrite result on failure' => fwrite($fh, 'foo'),
]);