What are the differences in error handling behavior between fopen and fgets functions in PHP, and how can developers leverage this knowledge to debug issues effectively?

When using the fopen function in PHP to open a file, if an error occurs (such as the file not existing), it will return false. However, when using the fgets function to read from the file, it will not explicitly throw an error if the file cannot be opened. This can lead to issues where developers may not realize that the file was not successfully opened until they try to read from it. To effectively debug issues related to file handling in PHP, developers should check the return value of the fopen function to ensure the file was successfully opened before attempting to read from it using fgets.

$file = fopen("example.txt", "r");

if ($file === false) {
    echo "Error opening file";
    exit;
}

while ($line = fgets($file)) {
    echo $line;
}

fclose($file);