Escaping string for LIKE

If I have a string, and I want to search for everything that starts with
that string then I could do:

SELECT * FROM users WHERE name LIKE string || '%';

Now, if string contains \, _ or % then it won't do what I expect.

Is there a built-in function that I can call to escape the string so
that it isn't special for LIKE, or is it a case of regexing and putting
a \ before each \, _ or %?

David