Would love help with debugging MacOS compilation errors

[kburchfiel]

Hi everyone,

I would love to create an Apple Silicon MacOS release for CWC25, but I'm running into some compilation errors. Given my very limited Mac experience, I would love any help that you all could provide.

First, I tried executing the following command within my root folder on a relatively recent MacBook Air (with an Apple Silicon chip):

clang++ cpp_world_clock.cpp -o build/cwc25 --std=c++20

This produced the following error:

cpp_world_clock.cpp:144:16: error: no type named 'zoned_time' in namespace 'std::chrono' 144 | std::chrono::zoned_time tz_time{tz_string, current_time};

It looks like Clang doesn't yet offer support for zoned_time().

Therefore, I tried using GCC version 15.2 instead. I used HomeBrew to download GCC, then ran the following code: (I used gcc-15 rather than gcc because the latter caused Clang to get used for the build attempt.)

gcc-15 cpp_world_clock.cpp -o build/cwc25 --std=c++20

This produced the following error:

fatal error: _bounds.h: No such file or directory 78 | #include <_bounds.h>

A quick search suggests that this might be an issue with HomeBrew's GCC build.

I imagine that I'll eventually be able to build the program using Clang once it receives support for zoned_time(); however, I would like to release an executable version earlier than that if possible. Please let me know if you have any suggestions!

[barracuda156]

You can install MacPorts and add a local overlay with the port from here (I have pushed a fix for non-powerpc builds now): https://github.com/macos-powerpc/powerpc-ports/tree/54ba56e74af5d25d35df05ad0a235345b82984ca/sysutils/cpp-world-clock
Then run:

sudo port -v sync
sudo port -v install cpp-world-clock

See: https://guide.macports.org/chunked/development.local-repositories.html
You only need a single port, that works with standard MacPorts installation: https://www.macports.org/install.php

P. S. I have no idea how Homebrew builds gcc, but if it enables -stdlib= flag and installs libstdc++, it might work with -stdlib=libstdc++ passed to the build.

[kburchfiel]

Thanks! Further GCC attempts have been unsuccessful, but I'll give your approach a try. I'm tempted to get my wife to upgrade to MacOS 26 to see whether the Clang compiler for that version has better support for zoned_time!

[barracuda156]

@kburchfiel Building with MacPorts should be reproducible, though I have no way to test anything on macOS 26. The port of gcc15 builds on it: https://ports.macports.org/port/gcc15/details