What is better to start reading about the linux API or about the Linux kernel?

Question

linux

Hello. I am learning the C language (without pluses) I want to learn how to program under Linux, ideally build my own distribution based on the kernel and write my own real-time programs, where is the best place to start? from which book: Linux API. The Comprehensive Guide or The Linux Kernel. Description of the development process, or Embedded systems based on Linux?

P.S. I read that based on the Linux kernel, you can build anything and it will not be large in size, but there are minimalistic distributions like slitaz

Answer 1

Linux systems programming Robert Love, linux programming interface Michael KerrisK

Answer 2

Linux API. Comprehensive guide

From him. Because this is exactly what you need to learn how to "program under Linux."