Tuesday, 6 April 2021

Preparing for a Github PR

This is a note about preparing a pull request (PR) for a Github repository. As much as anything, it’s to stop me having to page back through my lab notebook to find out how I did it last time …

Saturday, 6 March 2021

Developing for Cortex MCUs on a Raspberry Pi

Recently, on the Gitter Ada Programming Language lobby, there have been discussions on cross-compiling for Cortex M micro-controllers, specifically the BBC micro:bit, using the Raspberry Pi.

TL;DR: it's not going to be easy, unfortunately. Maybe later (or earlier?) Raspbian releases will help.

Monday, 10 June 2019

MacOS Software Development Kit changes

This post is based on the README from the corresponding Github repository.

That repository attempts to cope with expected changes in Apple’s approach to software development kits, specifically where to find the system headers (you’d expect /usr/include).

Sunday, 19 May 2019

Coding Guidelines


This is a rather self-satisfied document, written in the mid-1990’s, which may still have some relevance.

Coding Guide

Purpose and Scope

While it is hard to make a silk purse out of a sow’s ear (to create good code from a bad design), it is all too easy to do the reverse.

The principle that clear, readable, understandable source text eases program evolution, adaptation, and maintenance is not dependent on the programming language in which the text is written. The purpose of this document is to indicate those language-independent techniques which can help you to produce source text with these qualities.

Friday, 1 February 2019

Using GDB with a BBC micro:bit

This note is about using Segger J-Link software to help debug code on a BBC micro:bit.

Monday, 19 November 2018

Mojave vs. GCC

After you've installed Xcode (or, my preference, the Command Line Tools via xcode-select -install) so that you can install and use GNAT, you may expect to be able to compile C code too.

Mojave may surprise you with

$ gcc casing.c -o casing
casing.c:1:10: fatal error: stdio.h: No such file or directory
    1 | #include <stdio.h>
      |          ^~~~~~~~~
      compilation terminated.

The reason, according to this question and its answers, is that Apple's developer tools, in particular the clang compiler, know where to find the include files under /Library/Developer; GCC doesn't (I'm sure it could be made to, but ...) and so we have to add an extra step to install them in the normal place:

$ sudo installer -pkg /Library/Developer/CommandLineTools/Packages/macOS_SDK_headers_for_macOS_10.14.pkg -target /
installer: Package name is macOS_SDK_headers_for_macOS_10.14
installer: Installing at base path /
installer: The install was successful.
You may need to repeat this after macOS or Command Line Tools (or Xcode) updates.

Mojave vs. GDB

Apple's software development tools are based on LLVM, and Apple don't seem to feel it necessary to keep GCC and friends up to date with changes in the Apple tools or security policies.

GDB has been particularly affected by this. You can see why a tool which is capable of interacting with running programs would have to be treated with caution.