is_writable

Be warned, that is_writable returns false for non-existent files, although they can be written to the queried path.

In Linux, you might encountering an issue which is a file is not writable even tho it has 644 permission! The problem is with SELinux, just disable it or add rules to allow it.

To Darek and F Dot: About group permissions, there is this note in the php.ini file:; By default, Safe Mode does a UID compare check when; opening files. If you want to relax this to a GID compare,; then turn on safe_mode_gid.safe_mode_gid = Off

Check director is writable recursively. to return true, all of directory contents  must be writable<?phpfunction is_writable_r($dir) {    if (is_dir($dir)) {        if(is_writable($dir)){            $objects = scandir($dir);            foreach ($objects as $object) {                if ($object != "." && $object != "..") {                    if (!is_writable_r($dir."/".$object)) return false;                    else continue;                }            }                return true;            }else{            return false;        }            }else if(file_exists($dir)){        return (is_writable($dir));            }}?>

It appears that is_writable() does not check full permissions of a file to determine whether the current user can write to it.  For example, with Apache running as user 'www', and a member of the group 'wheel', is_writable() returns false on a file like-rwxrwxr-x           root         wheel          /etc/some.file

Regarding you might recognize your files on your web contructed by your PHP-scripts are grouped as NOBODY you can avoid this problem by setting up an FTP-Connection ("ftp_connect", "ftp_raw", etc.) and use methods like "ftp_fput" to create these [instead of giving out rights so you can use the usual "unsecure" way]. This will give the files created not the GROUP NOBODY - it will give out the GROUP your FTP-Connection via your FTP-Program uses, too.Furthermore you might want to hash the password for the FTP-Connection - then check out:http://dev.mysql.com/doc/mysql/en/Password_hashing.html

This file_write() function will give $filename the write permission before writing $content to it.Note that many servers do not allow file permissions to be changed by the PHP user.<?php    function file_write($filename, &$content) {         if (!is_writable($filename)) {            if (!chmod($filename, 0666)) {                 echo "Cannot change the mode of file ($filename)";                 exit;            };        }        if (!$fp = @fopen($filename, "w")) {            echo "Cannot open file ($filename)";            exit;        }        if (fwrite($fp, $content) === FALSE) {            echo "Cannot write to file ($filename)";            exit;        }         if (!fclose($fp)) {            echo "Cannot close file ($filename)";            exit;        }    } ?>

The results of this function seems to be not cached :Tested on linux and windows<?phpchmod($s_pathFichier, 0400);echo'<pre>';var_dump(is_writable($s_pathFichier));echo'</pre>';chmod($s_pathFichier, 04600);echo'<pre>';var_dump(is_writable($s_pathFichier));echo'</pre>';exit;?>

This function returns always false on windows, when you check an network drive.See PHP Bug https://bugs.php.net/bug.php?id=68926See https://stackoverflow.com/q/54904676