My goal is to have standalone assembly programs. However, when structs or data items are returned from OS calls, I want to be able to map those accurately (and painlessly) as well. What are the tricks you refer to? Writing a C program to write out equates for field offsets would technically work, but it's pretty ugly and a PITA to maintain, as it's really just magic numbers at that point. I saw in the last version of Xcode (the version that was associated with El Capitan) I could choose NASM instead of the MAC OS assembler. Should I be using NASM instead? I haven't looked to see if that's still an option in 15.2. I've perused the build options but didn't see it yet. (I'm on Ventura now). My research into the lack off support for structs/unions in the Mac OS assembler harkens of a big road block sign that says "DO NOT ENTER", as without support for structures, it's really not a viable development option. I've written in assembler since 1984, but not on this platform. As a side question... I'd be up for upgrading to a MacBook Pro, and writing assembler for the ARM instead of Intel, but will I hit the same native lack of support there too? Thanks!

Never mind. I found it. To get to it now, (unless there is a quicker way), on the row of icons above the "blue box", on the right end, there is a "report" icon for "Show the Report navigator". Click on that, then find the log you want to look at, click it, and then in the main frame, you will see the Build Log for the project. The failing step will have a grey background, and on the far right end of the grey line, click the icon with the lines, and the report will become visible.