Symfony\Component\Process\PhpProcess::getPhpBinary PHP Method

    public static function getPhpBinary()
    {
        if (getenv('PHP_PATH')) {
            if (!is_executable($php = getenv('PHP_PATH'))) {
                throw new \RuntimeException('The defined PHP_PATH environment variable is not a valid PHP executable.');
            }
            return $php;
        }
        $suffixes = DIRECTORY_SEPARATOR == '\\' ? getenv('PATHEXT') ? explode(PATH_SEPARATOR, getenv('PATHEXT')) : array('.exe', '.bat', '.cmd', '.com') : array('');
        foreach ($suffixes as $suffix) {
            if (is_executable($php = PHP_BINDIR . DIRECTORY_SEPARATOR . 'php' . $suffix)) {
                return $php;
            }
        }
        throw new \RuntimeException('Unable to find the PHP executable.');
    }