I just learned about this book Systems Programming with Zig. I’m reading through the free introductory chapters to familiarize myself with things I thought I’d already know. But, as a college drop-out, I think there are a handful of low level concepts I missed, and buffer flushing was one of them!

Reflection

Zig is all about removing implicit behavior. Its number one of the zig zen after all:

nate in ~/source/zig-systems on main λ zig zen

 * Communicate intent precisely.
 * Edge cases matter.
 * Favor reading code over writing code.
 * Only one obvious way to do things.
 * Runtime crashes are better than bugs.
 * Compile errors are better than runtime crashes.
 * Incremental improvements.
 * Avoid local maximums.
 * Reduce the amount one must remember.
 * Focus on code rather than style.
 * Resource allocation may fail; resource deallocation must succeed.
 * Memory is a resource.
 * Together we serve the users.

When you want to write some text to the console, the program needs to make a syscall to actually send that data to the OS, to then print out those characters. By default, most languages flush buffers for you, because when you call writeOut("some text"), you expect it to write it! But, to save on syscalls, zig will buffer those bytes, and any more bytes, until you tell it to flush(), which then tells your program to make the syscall so we can see those beautiful bytes.