PHP | is_writable() Function

The is_writable() function in PHP used to check whether the specified file is writable or not. The name of the file is sent as a parameter to the is_writable() function and it returns True if the filename exists and is writable.
Name of a directory can also be a parameter to the is_writable() function which allows checking whether the directory is writable or not.

Syntax:

is_writable(file)

Parameters Used:
The is_writable() function in PHP accepts one parameter.

• file : It is a mandatory parameter which specifies the file.

Return Value:
It returns True if the filename exists and is writable.

Exceptions:

1. An E_WARNING is emitted on failure.
2. The result of this function are cached and therefore the clearstatcache() function is used to clear the cache.
3. is_writable() function returns false for non-existent files.

Examples:

Input : $myfile = "gfg.txt";
        if(is_writable($myfile)) 
        {
           echo ("$myfile file is writable!");
        } 
        else 
        {
           echo ("$myfile file is not writable!");
        }
Output : gfg.txt file is writable!

Input : $permissions = fileperms("gfg.txt");
        $perm_value = sprintf("%o", $permissions);
        $myfile = "gfg.txt";
       
        if (is_writable($myfile)) 
        {
          echo ("$myfile file is writable and
          it has the following file permissions : $perm_value");
        } 
        else 
        {
          echo ("$myfile file is not writable and
          it has the following file permissions : $perm_value");
        }

Output : gfg.txt file is writable and it has the following file permissions : 0664

Below programs illustrate the is_writable() function.

Program 1

<?php
$myfile = "gfg.txt";

// checking whether the file is writable or not
if(is_writable($myfile))
{
 echo ("$myfile file is writable!");
}
else
{
 echo ("$myfile file is not writable!");
}
?>

Output:

 gfg.txt file is writable!

Program 2

<?php
// checking permissions of the file
$permissions = fileperms("gfg.txt");
$perm_value = sprintf("%o", $permissions);

// Clearing the File Status Cache
clearstatcache();

$myfile = "gfg.txt";

// checking whether the file is writable or not
if(is_writable($myfile))
{
 echo ("$myfile file is writable and
   it has the following file permissions : $perm_value");
}
else
{
 echo ("$myfile file is not writable and
   it has the following file permissions : $perm_value");
}

// Clearing the File Status Cache
clearstatcache();
?>

Output:

gfg.txt file is writable and it has the following file permissions : 0664

Reference:
http://php.net/manual/en/function.is-writable.php