protected function getSignalList(): array
    {
        if (null !== self::$list) {
            return self::$list;
        }

        $signals = [
            SIGHUP,
            SIGINT,
            SIGQUIT,
            SIGILL,
            SIGABRT,
            SIGTRAP,
            SIGBUS,
            SIGTERM,
            SIGSEGV,
            SIGFPE,
            SIGALRM,
            SIGVTALRM,
            SIGPROF,
            SIGIO,
            SIGCONT,
            SIGURG,
            SIGPIPE,
            SIGXCPU,
            SIGXFSZ,
            SIGTTIN,
            SIGTTOU,
            SIGUSR1,
            SIGUSR2,
        ];

        if (defined('SIGIOT')) {
            $signals[] = SIGIOT;
        }

        if (defined('SIGSTKFLT')) {
            $signals[] = SIGSTKFLT;
        }

        if (defined('SIGCLD')) {
            $signals[] = SIGCLD;
        }

        if (defined('SIGCHLD')) {
            $signals[] = SIGCHLD;
        }

        return self::$list = $signals;
    }
protected function getSignalList(): array
    {
        if (null !== self::$list) {
            return self::$list;
        }

        $signals = [
            SIGHUP,
            SIGINT,
            SIGQUIT,
            SIGILL,
            SIGABRT,
            SIGTRAP,
            SIGBUS,
            SIGTERM,
            SIGSEGV,
            SIGFPE,
            SIGALRM,
            SIGVTALRM,
            SIGPROF,
            SIGIO,
            SIGCONT,
            SIGURG,
            SIGPIPE,
            SIGXCPU,
            SIGXFSZ,
            SIGTTIN,
            SIGTTOU,
            SIGUSR1,
            SIGUSR2,
        ];

        if (defined('SIGIOT')) {
            $signals[] = SIGIOT;
        }

        if (defined('SIGSTKFLT')) {
            $signals[] = SIGSTKFLT;
        }

        if (defined('SIGCLD')) {
            $signals[] = SIGCLD;
        }

        if (defined('SIGCHLD')) {
            $signals[] = SIGCHLD;
        }

        return self::$list = $signals;
    }
protected function getSignalList ( ) : array { if ( null !== self :: $ list ) { return self :: $ list ; } $ signals = [ SIGHUP , SIGINT , SIGQUIT , SIGILL , SIGABRT , SIGTRAP , SIGBUS , SIGTERM , SIGSEGV , SIGFPE , SIGALRM , SIGVTALRM , SIGPROF , SIGIO , SIGCONT , SIGURG , SIGPIPE , SIGXCPU , SIGXFSZ , SIGTTIN , SIGTTOU , SIGUSR1 , SIGUSR2 , ] ; if ( defined ( 'SIGIOT' ) ) { $ signals [ ] = SIGIOT ; } if ( defined ( 'SIGSTKFLT' ) ) { $ signals [ ] = SIGSTKFLT ; } if ( defined ( 'SIGCLD' ) ) { $ signals [ ] = SIGCLD ; } if ( defined ( 'SIGCHLD' ) ) { $ signals [ ] = SIGCHLD ; } return self :: $ list = $ signals ; }
Returns an array of signals to be handled. Exploits the fact that PHP will not notice the signal constants are
undefined if the pcntl extension is not installed.

@return int[]
Returns an array of signals to be handled . Exploits the fact that PHP will not notice the signal constants are undefined if the pcntl extension is not installed .