Retro68 VS executor

If you can live with cross-compiling from a modern PC (or Mac) you can use https://github.com/autc04/Retro68 which uses a recent version of GCC.

Alternatively, you could install Executor 2000 (sort of a Wine-like clean-room reimplementation of Macintosh System 6 for running on other OSes) and get into classic MacOS programming using the GCC-based Retro68 C++-17 toolchain.

Strongly recommend checking out Retro68 and cross compiling from a newer machine: https://github.com/autc04/Retro68

There are some really good Retro68 code examples out there as well. I started compiling a list here, including a couple of my own: https://henlin.net/2021/12/21/Cool-Retro68-projects/

As a few other folks have said, the inside Macintosh books are extremely valuable references for Mac-specific code. I keep pdfs of them open the whole time I’m working on my Macintosh projects.

if you want to go period-appropriate, you can run Macintosh Programmer's Workshop or CodeWarrior natively

I use retro68 on linux, which is a modern GCC toolchain, so it's just like developing any other C/C++ (well, without some nice debugging tools, and with the added complexity of the mac OS resource stuff)

https://github.com/autc04/Retro68/

personally, I think retro68 (port of modern GCC for vintage macs) is way nicer to use than any period-correct compilers or IDEs.

Alternatively, you could install Executor 2000 (sort of a Wine-like clean-room reimplementation of Macintosh System 6 for running on other OSes) and get into classic MacOS programming using the GCC-based Retro68 C++-17 toolchain.