File Permissions and CHMOD: How to set 777 in PHP upon file creation?

A question about file permissions when saving a file that when non existent, is created initially as new file.

Now, this all goes well, and the saved file appear to have mode 644.

What to I have to change here, in order to make the files save as mode 777?

/* write to file */

   self::writeFileContent($path, $value);

/* Write content to file
* @param string $file   Save content to which file
* @param string $content    String that needs to be written to the file
* @return bool
*/

private function writeFileContent($file, $content){
    $fp = fopen($file, 'w');
    fwrite($fp, $content);
    fclose($fp);
    return true;
}

PHP has a built in function called bool chmod(string $filename, int $mode )

http://php.net/function.chmod

private function writeFileContent($file, $content){
    $fp = fopen($file, 'w');
    fwrite($fp, $content);
    fclose($fp);
    chmod($file, 0777);  //changed to add the zero
    return true;
}