Building a hello world application

Revision as of 17:25, 17 July 2007

Preparation

This guide assumes that you have performed the steps in Building_OpenMoko_from_scratch

The commandline program

Store the following more or less standard hello world code in hello.c

#include <stdio.h>

int main()
{
  printf ("Hello World\n");
  return 0;
}

Compiling it the wrong / easy way

Assuming your current working directory is /home/moko,
and that you stored the code in /home/moko/hello.c

It should now be possible to compile the application using

./build/tmp/cross/arm-linux/bin/gcc -o hello hello.c

Testing it

Assuming you have followed Setting up USB connection and you have a working network concetion to either a qemu Neo or a real Neo.

scp hello root@192.168.0.202:/tmp/
ssh root@192.168.0.202 /tmp/hello

This sequence of commands ought to give you a nice Hello World, btw. the default root password is blank, just press return.

Why was it the wrong way?

OpenMoko uses [OpenEmbedded] and they use bitbake when building stuff

Compiling it using bitbake

If you set your enviroment (I created a small script to do this, you could also add it to you .bashrc)

export OMDIR=/home/moko
export BBPATH=$OMDIR/build:$OMDIR/openmoko/trunk/oe:$OMDIR/openembedded

You should be capable of

cd $OMDIR/build
bitbake nano

This should auto-magically fetch the recipe for baking nano and baking it.
This results in some ipk packages being created in $OMDIR/build/tmp/deploy/ipk/armv4t/

An OpenEmbedded guide to creating a hello world

OpenEmbedded has a nice [Wiki page] on creating a hello world, I highly recommend it.

Creating an ipk package

To be written (Perhaps this is done by the do_install() function)