hello-world-application.rst

Hello World application

Let's start with the Rafiki "Hello World" application. It examplifies what an application is and how to build and run it.

It consists of two files; main.rs and Makefile.

main.rs

main.rs<examples/hello_world/main.rs> defines the application entry function main().

#[macro_use] extern crate rafiki;

use rafiki::kernel::sys;

#[no_mangle]
pub fn main(_: isize, _: *const *const u8) -> isize
{
    sys::start();

    println!("Hello World!");

    0
}

Makefile

Makefile<examples/hello_world/Makefile> contains build configuration of the application.

NAME = hello_world
BOARD ?= linux

RAFIKI_ROOT = ../..
include $(RAFIKI_ROOT)/make/app.mk

Build and run

Cross-compile, link and then run on an Arduino Due:

$ cd examples/hello_world
$ make -s BOARD=arduino_due run
<build system output>
Hello world!
$