What is the equivalent of the Windows SDK on macOS?

Question

C++ / C#

Tell me how to perform operations with files and memory using OS tools, and not programming systems?

I have the following task:

An array of type BYTE with a size of 256 KB is given. Copy this array through the file on
disk to memory 10 times block by block. The size of the read block is 128-1024 bytes, the size of the
write block is taken equal to the size of the read block.

Windows has its own api, but what to use on macOS?
couldn't find the books
thank you