Is there any way to show, or throw, a PHP warning?

Question

I have a `select()` method in a database class, that has an optional boolean argument `$sum`. This argument is used to say if the method should use `COUNT(*)` or not too. I would like to show a warning, like those normal PHP errors, if I try to access `$class->sum` if the attribute is not set (i.e. when I call `select()` with `$sum == false`. Is there any way to show a warning like this, or I should just echo an error and be happy?

Accepted Answer

If you want to generate a warning, you should write

```
trigger_error($yourErrorMessage, E_USER_WARNING);
```

`trigger_error()` has the `$error_type` parameter for setting the error level (`Notice`, `Warning` or `Fatal error`). The constants are, respectively:

```
E_USER_NOTICE             // Notice (default)
E_USER_WARNING            // Warning
E_USER_ERROR              // Fatal Error
```

Note that `Fatal error` stops the execution of subsequent PHP code, while `Notice` and `Warning` let it continue.

From PHP 5.5, you should also consider the Finally statement.

Is there any way to show, or throw, a PHP warning?

Solution

Problem