_IsADefinition example

return $this->_parseFeaturesHeaderFile($features_header_file);
        } // no cpp
        return $this->_fromGlibCTest();
    }

    function _parseFeaturesHeaderFile($features_header_file)
    {
        $features_file = fopen($features_header_file, 'rb');
        while (!feof($features_file)) {
            $line = fgets($features_file, 8192);
            if (!$this->_IsADefinition($line)) {
                continue;
            }
            if (strpos($line, '__GLIBC__')) {
                // major version number #define __GLIBC__ version                 $line = preg_split('/\s+/', $line);
                $glibc_major = trim($line[2]);
                if (isset($glibc_minor)) {
                    break;
                }
                continue;
            }