Rounding using arbitrary precision libraries in PHP

Question

I asked a question earlier about how to deal with rounding issues with floating point numbers in PHP , and was pointed to the bc and gmp libraries.

I've looked at the functions in these libraries but nothing jumped out at me when I was looking for one to round off the number.

How do you accurately round using these libraries?

Answer 1

In How to ceil, floor and round bcmath numbers? , the answer gives you an implementation of bcround function, which utilizes its own bcfloor and bcceil function which seems to work.

As a test, here is what you asked for in your comment.

echo bcround(16.99225, 4); // outputs 16.9923