How to use function in preg_replace?

Question

PHP

In general, there is this code:
preg_replace("/тут неважно что/", "$1$2", str);
Regular return 2 brackets, how can I do something like this:

preg_replace("/тут неважно что/", my_func($1, $2), str);

That is, pass them to the function, and preg_replace to accept the result of its call.

Answer 1

preg_replace_callback ?