Zig fails to build my project with unhelpful error message

LaBatata101 · October 24, 2025, 1:47pm

After adding this code to my project, the compiler fails to build it with no error message at all. I’m using Zig version 0.15.2.

Here’s the error message:

install
└─ install ness
   └─ compile exe ness Debug native failure
error: the following command terminated unexpectedly:
/home/labatata/Downloads/zig-x86_64-linux-0.15.2/zig build-exe -fllvm -fno-strip -ODebug --dep ness -Mroot=/home/labatata/Code/Zig/8bit-emulator/src/main.zig .zig-cache/o/f517a313cf88065690fe32b3cd42db0d/libSDL3.a .zig-cache/o/d75169ef4a66fad01dafda99fda166d4/libblip_buf.a -I .zig-cache/o/a405d7d25f945e38b8a0cca5dd710db8 -I /home/labatata/Code/Zig/8bit-emulator/third-party/blip_buf-1.1.0 -I .zig-cache/o/a6fb089e932f705ef1065695b36c6e90 -Mness=/home/labatata/Code/Zig/8bit-emulator/src/root.zig -lc --cache-dir .zig-cache --global-cache-dir /home/labatata/.cache/zig --name ness --zig-lib-dir /home/labatata/Downloads/zig-x86_64-linux-0.15.2/lib/ --listen=-

Build Summary: 7/10 steps succeeded; 1 failed
install transitive failure
└─ install ness transitive failure
   └─ compile exe ness Debug native failure

error: the following build command failed with exit code 1:
.zig-cache/o/e1b6bfd2cde9b06c346af1f0902faeb9/build /home/labatata/Downloads/zig-x86_64-linux-0.15.2/zig /home/labatata/Downloads/zig-x86_64-linux-0.15.2/lib /home/labatata/Code/Zig/8bit-emulator .zig-cache /home/labatata/.cache/zig --seed 0xd8929d99 -Zcb851105fa437907

I’ve already tried deleting the cache but got the same error.

tobyjaffey · October 24, 2025, 1:54pm

I don’t know why, but here are some steps which are showing more info:

zig build --verbose-link --verbose-air --verbose-cc --debug-rt

error: the following command terminated unexpectedly:
/Users/trj/Desktop/org/zig/zig0152/zig-aarch64-macos-0.15.2/zig build-exe -fllvm -fno-strip -ODebug --dep ness -Mroot=/Users/trj/Desktop/org/zig/git/NESS/src/main.zig .zig-cache/o/4ab1b25ddbc6620ff963b19e5172a8fe/libSDL3.a .zig-cache/o/53405497440d7e3817a7dd3351ef314d/libblip_buf.a -I .zig-cache/o/0fc21f84b22e5c6866935b635cc15b29 -I /Users/trj/Desktop/org/zig/git/NESS/third-party/blip_buf-1.1.0 -I .zig-cache/o/a6fb089e932f705ef1065695b36c6e90 -Mness=/Users/trj/Desktop/org/zig/git/NESS/src/root.zig -framework CoreMedia -framework CoreVideo -framework Cocoa -weak_framework UniformTypeIdentifiers -framework IOKit -framework ForceFeedback -framework Carbon -framework CoreAudio -framework AudioToolbox -framework AVFoundation -framework Foundation -framework GameController -framework Metal -framework QuartzCore -weak_framework CoreHaptics -lc --verbose-air --verbose-link --verbose-cc --cache-dir .zig-cache --global-cache-dir /Users/trj/.cache/zig --debug-rt --name ness --zig-lib-dir /Users/trj/Desktop/org/zig/zig0152/zig-aarch64-macos-0.15.2/lib/ --listen=-

So, I run that by hand (skipping the final --listen=-)

/Users/trj/Desktop/org/zig/zig0152/zig-aarch64-macos-0.15.2/zig build-exe -fllvm -fno-strip -ODebug --dep ness -Mroot=/Users/trj/Desktop/org/zig/git/NESS/src/main.zig .zig-cache/o/4ab1b25ddbc6620ff963b19e5172a8fe/libSDL3.a .zig-cache/o/53405497440d7e3817a7dd3351ef314d/libblip_buf.a -I .zig-cache/o/0fc21f84b22e5c6866935b635cc15b29 -I /Users/trj/Desktop/org/zig/git/NESS/third-party/blip_buf-1.1.0 -I .zig-cache/o/a6fb089e932f705ef1065695b36c6e90 -Mness=/Users/trj/Desktop/org/zig/git/NESS/src/root.zig -framework CoreMedia -framework CoreVideo -framework Cocoa -weak_framework UniformTypeIdentifiers -framework IOKit -framework ForceFeedback -framework Carbon -framework CoreAudio -framework AudioToolbox -framework AVFoundation -framework Foundation -framework GameController -framework Metal -framework QuartzCore -weak_framework CoreHaptics -lc --verbose-air --verbose-link --verbose-cc --cache-dir .zig-cache --global-cache-dir /Users/trj/.cache/zig --debug-rt --name ness --zig-lib-dir /Users/trj/Desktop/org/zig/zig0152/zig-aarch64-macos-0.15.2/lib/
Trace/BPT trap: 5ng

https://stackoverflow.com/questions/14675206/what-is-trace-bpt-trap-5 says:

It has to do with not being able to find/load a dylib, which is specific to OSX. Which one it can’t find, is as you have found out is application specific.

LaBatata101 · October 24, 2025, 2:05pm

Running that command without the --listen=- results in a segmentation fault (core dumped) on my machine.

rpkak · October 24, 2025, 2:05pm

This seems like a compiler bug ~~in the llvm codegen on inline functions~~ (Edit: the bug is most likely in an earlier compiler step, but has to do with inline functions). You don’t hit it, if you remove the inline keyword of functions.

LaBatata101 · October 24, 2025, 2:08pm

That was it, thanks!

rpkak · October 24, 2025, 2:40pm

github.com/ziglang/zig

Function pointer to inline function causes linker error

opened 09:57AM - 04 Jan 24 UTC

ssmid

bug frontend

### Zig Version 0.12.0-dev.1871+e426ae43a ### Steps to Reproduce and Obser…ved Behavior ```zig const std = @import("std"); inline fn predict_fun() bool { return will_have_fun(); } fn will_have_fun() bool { if (@import("builtin").os.tag == .windows) { return false; } else { return true; } } pub fn main() !void { // the @ptrCast makes sense when using interfaces where *anyopaque is used, see snippet below const predict_fun_p: *const fn () bool = @ptrCast(&predict_fun); std.debug.print("Will have fun: {}\n", .{predict_fun_p()}); } ``` This causes a linker error: ```bash error: ld.lld: undefined symbol: test2.predict_fun note: referenced by test2.zig:17 note: ~/.cache/zig/o/4387975daf2b9165b432ee8243712986/test2.o:(test2.main) note: referenced by test2.zig:18 note: ~/.cache/zig/o/4387975daf2b9165b432ee8243712986/test2.o:(test2.main) ``` Use case where this is an issue: ```zig const std = @import("std"); var gpa = std.heap.GeneralPurposeAllocator(.{}){}; const allocator = gpa.allocator(); const FunPredictorInterface = struct { obj: *anyopaque, predict_fun_fn: *const fn(*const anyopaque) bool, fn predict_fun(self: *const @This()) bool { return self.predict_fun_fn(self.obj); } }; const FunPredictor3 = struct { unneccessary: u32 = 1, inline fn predict_fun(self: *const @This()) bool { _ = self; return will_have_fun(); } }; fn choose_fun_predictor() !FunPredictorInterface { const fun_predictor = try allocator.create(FunPredictor3); fun_predictor.* = FunPredictor3{}; return .{ .obj = @ptrCast(fun_predictor), // predict_fun must be cast because interface uses *anyopaque // but function pointer to inline function should probably not be allowed .predict_fun_fn = @ptrCast(&FunPredictor3.predict_fun), }; } fn will_have_fun() bool { if (@import("builtin").os.tag == .windows) { return false; } else { return true; } } pub fn main() !void { const fun_predictor = try choose_fun_predictor(); std.debug.print("Will have fun: {}\n", .{fun_predictor.predict_fun()}); } ``` ### Expected Behavior ~The compiler throws an error when creating a reference (`&`) to a function that is marked as `inline`.~ See mlugg's answer below.