Fatal error: Uncaught Error: Undefined constant 'STDIN' in /opt/lampp/htdocs/squidv2-stage-cr/vendor/symfony/process/Tests/PipeStdinInStdoutStdErrStreamSelect.php:17 Stack trace: #0 {main} thrown in /opt/lampp/htdocs/squidv2-stage-cr/vendor/symfony/process/Tests/PipeStdinInStdoutStdErrStreamSelect.php on line 17