Get hello world compiling for iOS

I'm just figuring out at what point in time you are with iOS support for Zig. I tried to compile the basic project that you get when you initialize a new Zig project with the following command:

zig build-exe ./src/main.zig -target aarch64-ios

And I get the following error:

/usr/local/Cellar/zig/0.6.0_1/lib/zig/std/debug.zig:662:21: error: openSelfDebugInfo unsupported for this platform
            else => @compileError("openSelfDebugInfo unsupported for this platform"),
                    ^

Does that mean that iOS is not supported at all or is there anything I could do to help adding support for that platform?

Compiling a debug build (the default) has safety features enabled, and many of these things are OS specific. If you want to make good use of zig's runtime safety features, someone would have to implement these for IOS.

Large areas of the standard library as a whole likely won't be available yet.

For now, I think IOS will work in release fast and release small (providing you can avoid using a lot of the standard library).

Both release-fast and release-small seem to fail with the same error. Am I doing something wrong?

➜  test-zig zig build-exe ./src/main.zig -target aarch64-ios --release-fast
/usr/local/Cellar/zig/0.6.0_1/lib/zig/std/debug.zig:662:21: error: openSelfDebugInfo unsupported for this platform
            else => @compileError("openSelfDebugInfo unsupported for this platform"),
                    ^
➜  test-zig zig build-exe ./src/main.zig -target aarch64-ios --release-small
/usr/local/Cellar/zig/0.6.0_1/lib/zig/std/debug.zig:662:21: error: openSelfDebugInfo unsupported for this platform
            else => @compileError("openSelfDebugInfo unsupported for this platform"),
                    ^

Am I doing something wrong?

The --release-* switches won't do anything for your problem. Try adding .ios in the switch where the @compilError is, I believe the Darwin codepath works just fine on IOS too.

So far my src/main.zig file (the only one I have besides the build.zig) is the following:

const std = @import("std");

pub fn main() anyerror!void {
    std.debug.warn("All your codebase are belong to us.\n", .{});
}

I even tried this because I thought std.debug could be the issue:

const std = @import("std");

pub fn main() anyerror!void {
    const stdout = std.io.getStdOut().outStream();
    try stdout.print("Hello, {}!\n", .{"world"});
}

but the error is still the same.
I don't get where I should add an .ios to a switch... which switch? :)

The --release-* switches won't do anything for your problem. Try adding .ios in the switch where the @compilError is, I believe the Darwin codepath works just fine on IOS too.

wait..... why is ios different to darwin? they're the same kernel

@daurnimator

@daurnimator yes it is the same kernel. But if I add .ios to this switch in the std library (I believe this is the switch @LemonBoy was referring to) then it compiles:

/// TODO resources https://github.com/ziglang/zig/issues/4353
pub fn openSelfDebugInfo(allocator: *mem.Allocator) anyerror!DebugInfo {
    noasync {
        if (builtin.strip_debug_info)
            return error.MissingDebugInfo;
        if (@hasDecl(root, "os") and @hasDecl(root.os, "debug") and @hasDecl(root.os.debug, "openSelfDebugInfo")) {
            return root.os.debug.openSelfDebugInfo(allocator);
        }
        switch (builtin.os.tag) {
            .linux,
            .freebsd,
            .netbsd,
            .dragonfly,
            .macosx,
            .windows,
            .ios,
            => return DebugInfo.init(allocator),
            else => @compileError("openSelfDebugInfo unsupported for this platform"),
        }
    }
}

I don't get where I should add an .ios to a switch... which switch? :)

The one above /usr/local/Cellar/zig/0.6.0_1/lib/zig/std/debug.zig:662. I'd suggest you to fetch a copy from git to avoid modifying the homebrew copy.

wait..... why is ios different to darwin? they're the same kernel

I forgot to put back the .ios, .watchos and friends when I refactored the debug stuff.

@LemonBoy

@LemonBoy hah! now that's clear :)

Ok, then I have one more question regarding compiling for iOS. Let's assume that:

I have a C library that I wrote that I use to make games on all kind of platforms with.
In that library I am including SDL2 and other libraries as source code and compile them all statically into my library to make sure that I'm using the same versions that I have written my code with.
I believe that Zig has no clue about CMake files
But Zig is using clang to compile C code, so I guess it should be able to understand Obj-C code, too

Would it be possible to provide to Zig a list of folders with the source code of SDL2 and the like and write a build.zig script that compiles all of them with the correct inclusion files and the correct switches for clang and also for the Obj-C files?

@tanis2000

@tanis2000 you're prolly gonna need to dive into this, update SDL and add iOS to the build script: https://github.com/andrewrk/zig-sdl

@prime31

@prime31 I already did all of that in my own repo without all the extra stuff of that SDL repo. But I still have issues compiling for macOS, not even iOS... Actually the compiler itself is crashing: #5188

Would it be possible to provide to Zig a list of folders with the source code of SDL2 and the like and write a build.zig script that compiles all of them with the correct inclusion files and the correct switches for clang and also for the Obj-C files?

Yes, and you can see a proof-of-concept here: https://github.com/andrewrk/zig-sdl

@SebastianKeller

@SebastianKeller,
Running the steps you listed produces
dyld: Symbol not found: __tlv_bootstrap

Any idea what might be causing this? I'm running zig 0.7.1 and the simulator is iOS 14.3.

The symbol is defined on master, not 0.7.1

@g-w1

@g-w1, Thanks that would explain it. As a zig newbie, are builds of master available to install?
If not, I'll compile from source, a good way to learn the system.

They are avaliable on the download page.

…

On Wed Feb 3, 2021 at 2:33 PM, coolbluewater wrote: @g-w1, Thanks that would explain it. As a zig newbie, are builds of master available to install? If not, I'll compile from source, a good way to learn the system. -- You are receiving this because you were mentioned. Reply to this email directly or view it on GitHub: #5145 (comment)

@coolbluewater

@coolbluewater
https://ziglang.org/download/

https://ziglang.org/builds/zig-macos-x86_64-0.8.0-dev.1119+2d447b57c.tar.xz thats the version i used

@g-w1

@g-w1, @SebastianKeller - thanks all. Will report back.

@SebastianKeller

@SebastianKeller, running xcrun simctl spawn works, and the output is in Terminal.

But running the .app bundle doesn't seem to produce any output in Console. Investigating.

Update: while I'm still unable to find where the "Hello, world" got written to, adding this worked:

std.os.exit(1);

Now Console shows Service exited with abnormal code: 1
So that's probably the first iOS app written entirely in zig with no Objective-C or Swift! :)

hmm... don't app launchers close file handles 0,1,2 and force use of logging api ... and console.app can read?

@mikdusan

@mikdusan, you're probably correct. Now trying to use os_log.

What is the zig equivalent of Objective-C's#import <os/log.h>? This allows framework headers to be imported easily.

I tried const log = @import("os/log.h"); but that fails with or without the .h.

Edit: Think I may need to create an objective-C library with that exposes functionality to zig via the C ABI. Also opened #7944 to discuss whether Objective-C frameworks can be supported more directly in zig.

If you want to include the c library you probably want

const c = @cImport({
@cInclude("os/log.h");
});

@g-w1

@g-w1, unfortunately that doesn't work.
More detail: Apple frameworks have a known location and layout that clang uses to resolve #import <os/log.h> when parsing a source file as objective-c, but not as plain C. Since zig uses clang in plain-C mode to parse files, this mechanism isn't invoked and so the header can't be located. That's why I've opened the issue mentioned above to discuss the future of objective-C interop in zig.

@coolbluewater

@coolbluewater my buddy Bill just did some writing to the iOS console yesterday for us testing a Zig build (using the iOS SDK still). He used os_log(), which you should be able to create an extern for _os_log_internal to using this within your Zig app without needing the full SDK to build against. It was extremely helpful in our debugging yesterday (which we have working beautifully now). Man, Zig is great.

Navigation Menu

Repository navigation

Get hello world compiling for iOS #5145

13 remaining items

Metadata

Assignees

Labels

Type

Projects

Milestone

Relationships

Development

Get hello world compiling for iOS #5145

Description

Activity

Sobeston commented on Apr 23, 2020

tanis2000 commented on Apr 27, 2020

LemonBoy commented on Apr 27, 2020

tanis2000 commented on Apr 27, 2020

daurnimator commented on Apr 27, 2020

tanis2000 commented on Apr 27, 2020

LemonBoy commented on Apr 27, 2020

tanis2000 commented on Apr 27, 2020

prime31 commented on May 3, 2020

tanis2000 commented on May 4, 2020

andrewrk commented on May 30, 2020

13 remaining items

coolbluewater commented on Feb 3, 2021

g-w1 commented on Feb 3, 2021

coolbluewater commented on Feb 3, 2021

g-w1 commented on Feb 3, 2021

SebastianKeller commented on Feb 3, 2021

coolbluewater commented on Feb 3, 2021

coolbluewater commented on Feb 3, 2021

coolbluewater commented on Feb 3, 2021

mikdusan commented on Feb 3, 2021

coolbluewater commented on Feb 4, 2021

g-w1 commented on Feb 4, 2021

coolbluewater commented on Feb 4, 2021

kerrhome commented on Feb 17, 2021

Metadata

Metadata

Assignees

Labels

Type

Projects

Milestone

Relationships

Development

Issue actions