Chapter 6: System Programming

Sections 61--70 System programming is where C shines -- and where Auto chooses a different path.

C was born to write operating systems. Its standard library sits directly on top of kernel system calls, and every C programmer eventually learns about file descriptors, processes, signals, and memory mapping. Auto takes a higher-level approach: it wraps the dangerous primitives in safe APIs and does not expose raw syscalls.

This chapter is heavy on C-only concepts. We present them as essential knowledge for understanding how programs interact with the operating system, then show Auto's simplified alternatives where they exist.

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61. System Calls vs Standard Library

Every operating system provides a set of system calls -- functions that request services from the kernel. In C, you can call them directly:

/* Raw syscall */
ssize_t n = read(fd, buffer, sizeof(buffer));

/* Stdlib wrapper (buffers data, more portable) */
size_t n = fread(buffer, 1, sizeof(buffer), file);

The standard library wraps raw syscalls with buffering, error handling, and portability. fread() calls read() internally but adds a user-space buffer.

Auto goes further: functions like print(), read_file(), and write_file() hide all the syscall details entirely. You never deal with file descriptors or buffer management.