具体来说,“@有它的用途”：

Now one really should use the @ operator very sparingly,handling
errors instead of suppressing them. But there are a small number of
situations I can think of where one might need to suppress some PHP
errors. Let me offer two examples :

• You could be using some large external library which has made use of the @,and so need to be able to ignore those errors as the author
  of the library intended,otherwise your program is going to trip up
  where it doesn’t need to. You could edit the library,but it might
  take a lot of time,and your changes would again have to be applied
  each time the author releases an update to the library.

• Another example might be when the fopen function is used to open an external URL,and the URL cannot be opened for one of many possible
  reasons. The function returns false to indicate a fail,which is
  great,but to quote the PHP manual,“an error of level E_WARNING is
  generated” too,not so great — it should really result in an exception
  being thrown instead,as this is an irregular situation,but one which
  should be expected.
  In this case one would like to be able to ignore
  the error,and continue with the program execution,explicitly
  responding in an appropriate way – exactly what exceptions are for!
  There is,however,a way to convert the error to an exception and so
  avoid using the @ in this situation. In your custom error handler
  (which is where we find ourselves in this post),throw an
  ErrorException – this then requires you to explicitly catch and handle
  it in the code that was using the @ before,which is a better way of handling errors.