Question

Or do I must call set_error_handler() on beginning and restore_error_handler() on end of every of my methods ?

Answer 1

Not necessarily.

When your error handler returns false, it will continue to the next registered error handler. (usually the php default error handler).

So you could write your function in a way it only handles specific – custom written – error codes.

function newErrorHandler($errno, $errstr, $errfile, $errline) {
    if (checkIfyours) {
        // Do something.
    }
    return false;
}