How to check if a file is writable in PHP?

In PHP, you can check if a file is writable using the is_writable() function.

Here's an example:

$filename = 'path/to/file.txt';

if (is_writable($filename)) {
    echo 'File is writable.';
} else {
    echo 'File is not writable.';
}

In this example, the is_writable() function checks if the file $filename is writable and returns true if it is writable, and false otherwise. You can then use an if statement to conditionally execute code based on the result.