GCC + Makefile example

The purposes of this example are to:

1. Illustrate the use of rules in Makefiles
2. Illustrate the use of specific flags in GCC
3. Capitalize on the ability to stop compilation at the assembly stage to compare the usage of libraries with their absence

Structure:

• lib_hello_world: standard C hello world program developed using stdio.h
• no_lib_hello_world: non-standard C hello world programa developed using inline volatile x86-64 assembly

Both folders contain appropriate Makefiles. Considerations:

• The rule all generates all compilation stages, including assembly and object code (none are needed)
• The rule debug generates only the executable with debug symbols
• As per usual standards, clean is a phony rule that deletes anything other than the original source code of the program

Additional considerations

The implementation provided under no_lib_hello_world is, for all intents and purposes, an excessive exercise in overengineering, not anything students--or any sane person, for that matter--should be expected to reproduce on their own. It is exceedingly complicated, hard to read, and unportable to boot. Bear in mind it will only work in x86-64 UNIX, as it directly depends on its specifics.

In short, this is an academic example meant exclusively to display the build pipeline typically applied in C in full, and provide a brief, purely informative look under the hood. Under no circumstances should it be taken as a reference for good coding practices, industry standards, or indeed anything but a hazardous forey into the depths of what C is able to do as a language.

Also, I did promise students to show them an example of printing without relying on the standard library. Let this be my way of making good on that promise, and a proper deterrent on straying from the beautiful path marked by <stdio.h> and its succesors.