function2.php

<?php

function writeFile($fullpath, $content)
{
    if (!is_writable($fullpath)) {
        return false;
    }
    
    if (!$fp = fopen($fullpath,'w')) {
        return false;
    }

    if (!fwrite($fp,$content)) {
        return false;
    }
    
    return true;
}

function writeFile($fullpath, $content)
{
    if (!is_writable($fullpath) || !$fp = fopen($fullpath,'w')) || !fwrite($fp,$content)) {
        return false;
    }

    return true;
}

optimized