Fatal error: Uncaught Error: Undefined constant 'STDIN' in D:\xampp\htdocs\MCH MPOS Application\Webservice\vendor\symfony\process\Tests\PipeStdinInStdoutStdErrStreamSelect.php:17 Stack trace: #0 {main} thrown in D:\xampp\htdocs\MCH MPOS Application\Webservice\vendor\symfony\process\Tests\PipeStdinInStdoutStdErrStreamSelect.php on line 17