Zig std.log.info not printing anything with cross-compiled to AARCH64 binary

user_1007991 0
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I have copied a hello world Zig program and it runs fine locally on my Mac:

const std = @import("std");

pub fn main() anyerror!void {
    // Note that info level log messages are by default printed only in Debug
    // and ReleaseSafe build modes.
    std.log.info("All your codebase are belong to us.", .{});
}

test "basic test" {
    try std.testing.expectEqual(10, 3 + 7);
}

I then cross-compiled it to ARM:

zig build-exe src/main.zig -O ReleaseSmall --strip -target aarch64-linux

Seems to compile the right thing:

$ file ./main
./main: ELF 64-bit LSB executable, ARM aarch64, version 1 (SYSV), statically linked, stripped

Then I copied it to my Raspberry Pi running Ubuntu 22.

It also shows the file is recognized and runs without error, but it just doesn't print anything. I tried redirecting both stdout and stderr to a file but nothing comes out.

What can be the problem?

zig
2 Answers

Turns out the code I had copied was not the "real" hello world. It only prints to the console when it's built in debug mode.

The production-grade hello world in Zig is this:

const std = @import("std");

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

Compiling this the same way, it works both on Mac and when compiled to aarch64-linux and executed on my Raspberry Pi.

user_10079910

To add, std.log.info does not display in ReleaseFast or ReleaseSmall builds by default. You can change this by overriding the log level in your main zig file:

pub const log_level: std.log.Level = .info;

Or, you can print to stdout directly rather than using logging functions:

const std = @import("std");

pub fn main() !void {
    const stdout = std.io.getStdOut().writer();
    try stdout.print("Hello, world!\n", .{});
}
user_28214200
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