dbj DBJDBJ

Intentional API

It's not a formally defined spec or standard — it's a design philosophy Kelsey Hightower champions, borrowed from intent-based networking (Cisco, etc.) and applied to APIs and infrastructure.

The core idea: you declare what you want, not how to get it. The system figures out the path.

Kubernetes is the canonical example — you declare desired state, the control loop reconciles reality to match it. You never say "start container on node X, then update the load balancer" — you say "I want 3 replicas of this."

Contrast with imperative APIs: "do this, then that, then handle this error case." Intent-based APIs absorb the operational complexity on the platform side.

Dusan B. Jovanovic (DBJ) dbj@dbj.org

https://dusanjovanovic.org

SKILLS & EXPERIENCE

NOTE: only relevant examples from the extensive portfolio

ESSENTIAL FOR THE ROLE

I use C, commericaly since 1991. This is where I record what I know about allocating and managing 2D/1D arrays in C. And I keep on revisiting this doc and clarifying it ever more. Many times I cought myself re-discovering what I have stored in here. Please do not repeat the same mistake.

How to really think of 2D Arrays in C

Short answer is this:

         + -- int (*arp)[2][3] // 2D array pointer
         V
 +------------- int arr[2][3] -----------+

	/*

	This is benchmarking of a collection of matrix multiplication algorithms.
	Algorithms are kept as simple as possible. No structs are passed as arguments.
	No "clever" "generic" matrix macros are used

	Different compilers multiplied with different platforms multiplied selection
	of data types yield a complex picture of benchmarking results.

	Although here is strong hint for you: The simplest algorithm is the fastest.

	/*

	(c) 2022 by dbj@dbj.org CC BY SA 4.0

	Godbolt: https://godbolt.org/z/ne579e85f

	The point is here we do not use naked pointer to pass the structs arround
	we use handles to the preallocated slabs of the same struct
	thus we do not suffer the perenial modern C dilema: should we pass the
	structs by value or as pointers to them.

	/*
	made 2021 by dbj@dbj.org

	https://godbolt.org/z/PjovPPoxf
	*/
	#include <assert.h>
	#include <math.h>
	#include <stdio.h>
	#include <stdlib.h>
	#define FOR(C, R) for (unsigned C = 0; C < R; ++C)

	// ----------------------------------------------
	// (c) 2021 by dbj@dbj.org
	// https://dbj.org/license_dbj
	// https://godbolt.org/z/vaMMrvM85
	// ----------------------------------------------
	#include <assert.h>
	#include <stdio.h>
	#include <stdlib.h>
	#include <string.h>
	#include <stdbool.h>

	#ifndef DBJ_DEFER_BEGIN_END_H
	#define DBJ_DEFER_BEGIN_END_H

	/*
	comment this in to see the demo
	#define DBJ_DEFER_BEGIN_END_DEMO 1
	*/
	/*
	2025-MAR dbj@dbj.org https://godbolt.org/z/adYP4ach4
	first seen it here https://youtu.be/QpAhX-gsHMs

	#define DBJ_MTX_TESTING

	// (c) 2019-2021 by dbj@dbj.org
	// License: CC BY SA 4.0

	#include <assert.h>
	#include <stdlib.h>
	#include <string.h> // memcpy

	namespace dbj::mtx {

	<!DOCTYPE html>
	<html lang="en">
	<head>
	<meta charset="utf-8">
	<!--
	removing this makes HTA:APPLICATION fully functional
	meta http-equiv="X-UA-Compatible" content="IE=edge"

	to be tested ...
	-->