Description:
------------
I use iis7.0 && php5.6.30(I also test in apache+php, the result is same) to run following php code

```
<?php
$cmd = "error_command || whoami";
exec($cmd, $output, $return_val);
var_dump($output);
var_dump($return_val);
?>
```

If the first command is wrong, then the second command wouldn't be executed, the output is

```
array(0) { } int(1)
```

But I run the code on windows+built-in webserver, the output is

```
array(1) { [0]=> string(12) "71ec\phithon" } int(0)
```

Cli's result:

```
F:\PHPStudy\WWW>F:\soft\php-5.6.30-Win32-VC11-x86\php.exe test\a.php
'error_command' 不是内部或外部命令，也不是可运行的程序
或批处理文件。
array(1) {
  [0]=>
  string(12) "71ec\phithon"
}
int(0)
```

So why php has 2 different results?

Test script:
---------------
<?php
$cmd = "error_command || whoami";
exec($cmd, $output, $return_val);
var_dump($output);
var_dump($return_val);
?>

Expected result:
----------------
array(1) { [0]=> string(12) "71ec\phithon" } int(0)

Actual result:
--------------
array(0) { } int(1)