Question

I’m a beginner in PHP. So far, from the source I’m learning from, the only mechanism to trigger an exception is by writing a line that throws it.

throw new Exception('message')

Furthermore, on the code below, any exception won’t be thrown, but an error will be raised.

try
{
    $file = fopen('no such file.txt', 'r');
}
catch(Exception $e)
{
    echo 'Exception: ' . $e->getMessage();
}

Please give me some explanations.
It seems this try..catch block is not so useful in PHP, unlike in Java or .NET.

Answer 1

“errors” are remains from the pre-oop era of php and are indeed hardly useful in the modern code. Fortunately, you can (actually, must) automatically convert most “errors” to exceptions. The magic is like this

function exception_error_handler($errno, $errstr, $errfile, $errline ) {
    throw new ErrorException($errstr, 0, $errno, $errfile, $errline);
}
set_error_handler("exception_error_handler");

Once you’ve got this, your “fopen” snippet will work as expected. See http://php.net/manual/en/class.errorexception.php for more details/discussion.