What are the potential pitfalls or errors that can occur when using the fwrite function in PHP, as seen in the user's code snippet?

The potential pitfalls or errors that can occur when using the fwrite function in PHP include not checking if the file was successfully opened before writing to it, not handling potential errors or exceptions that may occur during the writing process, and not properly closing the file after writing to it. To solve these issues, it is important to always check if the file was successfully opened, handle any errors or exceptions that may occur during writing, and properly close the file after writing to it.

$file = fopen("data.txt", "w");
if ($file) {
    if (fwrite($file, "Hello, World!") === false) {
        echo "Error writing to file.";
    }
    fclose($file);
} else {
    echo "Error opening file.";
}