private function closeExitCodePipe()
    {
        if ($this->sigchildPipe === null) {
            return;
        }

        \fclose($this->sigchildPipe);
        $this->sigchildPipe = null;
    }
private function closeExitCodePipe()
    {
        if ($this->sigchildPipe === null) {
            return;
        }

        \fclose($this->sigchildPipe);
        $this->sigchildPipe = null;
    }
private function closeExitCodePipe ( ) { if ( $ this -> sigchildPipe === null ) { return ; } \ fclose ( $ this -> sigchildPipe ) ; $ this -> sigchildPipe = null ; }
Close the fourth pipe used to relay an exit code.

This should only be used if --enable-sigchild compatibility was enabled.
Close the fourth pipe used to relay an exit code .