Zig Use Single .h File | Zig Programming Language | Page 1

mint pivot Jul 26, 2025, 4:28 AM

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I have been attempting to get a version of ENet working so I can use it in some Zig projects. (https://github.com/zpl-c/enet for reference). I did attempt to use the main version (https://github.com/lsalzman/enet) but I ended up with similar problems.

In after I build and compile it I end up with the error of raw_enet.zig:1:1: error: expected type expression, found \'invalid token\' ■

This is, unideal. I have tried using both zig translate-c and just writing my own pub extern fns in it's own file. Both give apparently the same error. I have even tried making a tiny '.c' file that does nothing but have an include statement of the header.

What I would like is to be able to use ENet. (Also the only one that I have found that has been wrapped for zig was last updated ~3 years ago.). I would also like to understand what I am doing wrong. The move I dive into the build system the more it feels like a black box. Thank you for your time and your help.

GitHub

GitHub - zpl-c/enet: ⚡️ ENet reliable UDP networking library

⚡️ ENet reliable UDP networking library . Contribute to zpl-c/enet development by creating an account on GitHub.

GitHub

GitHub - lsalzman/enet: ENet reliable UDP networking library

ENet reliable UDP networking library . Contribute to lsalzman/enet development by creating an account on GitHub.

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My Build file :


pub fn build(b : *std.Build) void {
    const target = b.standardTargetOptions(.{});
    const optimize = b.standardOptimizeOption(.{});

    const c_enet = b.addStaticLibrary(.{
        .target = target,
        .optimize = optimize,
        .link_libc = true,
        .name = "c_enet",
    });


    c_enet.linkLibC();
    c_enet.addIncludePath(b.path("enet/include"));
    c_enet.addCSourceFiles(
        .{.files = &[_][]const u8 {
            //"c_enet.c",
            "enet/include/enet.h",
        }},
    );
    b.installArtifact(c_enet);

    const raw_enet = b.createModule(.{
        .target = target,
        .optimize = optimize,
        .root_source_file = b.path("raw_enet.zig"),
        .link_libc = true,
    });
    raw_enet.linkLibrary(c_enet);



    const exe_module = b.createModule(.{
        .root_source_file = b.path("enet.zig"),
        .target = target,
        .optimize = optimize,
    });

    const exe = b.addExecutable(.{
        .name = "enet",
        .root_module = exe_module,
    });


    //exe.linkLibrary(c_enet);
    exe.root_module.addImport("raw_enet", raw_enet);
    b.installArtifact(exe);

    const run_cmd = b.addRunArtifact(exe);
    run_cmd.step.dependOn(b.getInstallStep());

    if (b.args) |args| {
        run_cmd.addArgs(args);
    }

    const run_step = b.step("run", "Run the app.");
    run_step.dependOn(&run_cmd.step);
}```

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raw_enet.zig :

pub extern fn enet_deinitialize() void;```

enet.zig : 
```const std = @import("std");
const raw_enet = @import("raw_enet");

const print = std.debug.print;

pub fn main() !void {
    const res = raw_enet.enet_initialize();
    print("{}\n", .{res});
}```

c_enet.c : 
`#include "enet.h"`

hollow saffron Jul 26, 2025, 5:02 AM

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if it's getting an invalid token at line 1 character 1 in the zig file, I wonder if this is an issue with the raw_enet.zig file having some sort of byte order mark

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and not really an issue with the API or library at all

mint pivot Jul 26, 2025, 5:04 AM

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hollow saffron and not really an issue with the API or library at all

I am on Windows and I read somewhere (I have long since forgotten, it has been a long day) that there is something weird when using translate-c on windows going on. But I am not even using that anymore

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I will copy and paste the text of raw_enet.zig into a new file and see if that does anything, but IDK

hollow saffron Jul 26, 2025, 5:04 AM

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you said it's AFTER you compile. that seems like an odd error to see while running your program, I'd think

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I'm a little too use to 0.15.0 changes to how build.zig works, so it's gonna take me a second to figure out the correct approach with zig 0.14.1

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I wonder if addImport is the right method tho. checking.

mint pivot Jul 26, 2025, 5:07 AM

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hollow saffron you said it's AFTER you compile. that seems like an odd error to see while runni...

Maybe I misspoke

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This is the build summary :

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run transitive failure
└─ run enet transitive failure
   ├─ zig build-exe enet Debug native 1 errors
   └─ install transitive failure
      └─ install enet transitive failure
         └─ zig build-exe enet Debug native (+3 more reused dependencies)```

hollow saffron Jul 26, 2025, 5:09 AM

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addImport is correct

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yeah I'd check the file in a hexeditor, and make sure the first character isn't a BOM

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but I already have one installed, so that's easier for me

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if you want to drop raw_enet.zig here I can check it

mint pivot Jul 26, 2025, 5:11 AM

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Alr

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📎 raw_enet.zig

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I am also downloading the latest dev; if that would be easier to debug.

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Also, thank you for your help. I appreciate it

hollow saffron Jul 26, 2025, 5:12 AM

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yeah it's got a BOM

mint pivot Jul 26, 2025, 5:13 AM

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Okay, can I ask what that is?

hollow saffron Jul 26, 2025, 5:13 AM

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it's extra bytes at the beginning of the file that tell programs what order to read the bytes when using multibyte character sets

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kinda some old junk, now that most things use utf-8

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you may want to use a different code editor

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📎 raw_enet.zig

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here it is without the BOM

mint pivot Jul 26, 2025, 5:14 AM

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Wait-wait wait. My problem is that I am using VS-Code?

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LOL

hollow saffron Jul 26, 2025, 5:15 AM

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vs code shouldn't cause problems. I don't know why it's doing that

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I was suspecting like notepad or wordpad or something

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let me know if that file gets you past the issue

mint pivot Jul 26, 2025, 5:16 AM

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It does; I now am getting : error: lld-link: undefined symbol: enet_initialize

hollow saffron Jul 26, 2025, 5:16 AM

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linker error

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you didn't actually link the library, you just effectlively imported a .h file

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addStaticLibrary just creates a new, empty library. the fact that you named it c_enet doesn't make it import that library

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a couple options:

get a path to a precompiled .lib for the library, and link that to your exe in your build.zig
add all the .c source files to that lib, in addition to that .h file, so that zig compiles the C code and puts it in that new empty static library you created in your build.zig

mint pivot Jul 26, 2025, 5:19 AM

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It is just a header file

hollow saffron Jul 26, 2025, 5:19 AM

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is it? I know nothing about it 😄

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maybe you need to define #define ENET_IMPLEMENTATION or something like that

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if it's a single-header lib

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the references I find to an enet library all look like they have .c files as well

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oh, a different one seems to be single-header

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is it this one? https://github.com/zpl-c/enet

GitHub

GitHub - zpl-c/enet: ⚡️ ENet reliable UDP networking library

⚡️ ENet reliable UDP networking library . Contribute to zpl-c/enet development by creating an account on GitHub.

mint pivot Jul 26, 2025, 5:21 AM

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I am using a modern iteration. Yeah that one

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I did try using the other one but I was running into something weird.

hollow saffron Jul 26, 2025, 5:21 AM

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at the top of the .h file, it says you need to #define ENET_IMPLEMENTATION

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nice. predicted it hehe

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so, there's a couple ways to do that:

mint pivot Jul 26, 2025, 5:22 AM

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Okay

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I made a tiny c-file

hollow saffron Jul 26, 2025, 5:23 AM

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create your own .c file and compile THAT in your lib, instead of the .h file. it will have JUST #define ENET_IMPLEMENTATION and #include enet.h
call the appropriate method to add the #define for your c source files. looking up that call now...

mint pivot Jul 26, 2025, 5:23 AM

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that just has

#include "enet.h"```

hollow saffron Jul 26, 2025, 5:23 AM

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yeah

mint pivot Jul 26, 2025, 5:23 AM

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Oh; good I did it right

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that's new

hollow saffron Jul 26, 2025, 5:23 AM

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there's an alternative option I can look up if your prefer, but sometimes I just do the .c file

mint pivot Jul 26, 2025, 5:24 AM

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unfortunately I am getting this error : error: lld-link: undefined symbol: __declspec(dllimport) WSAStartup note: referenced by C:\Users\default.LAPTOP-4MN3KEP0\Desktop\code\Zig\Testing\Bind_ZPL_Enet_take2\enet\include\enet.h:5881 note: c_enet.lib(c_enet.obj):(enet_initialize) error: lld-link: undefined symbol: __declspec(dllimport) WSACleanup note: referenced by ...\Bind_ZPL_Enet_take2\enet\include\enet.h:5886 note: c_enet.lib(c_enet.obj):(enet_initialize) note: referenced by ...\Bind_ZPL_Enet_take2\enet\include\enet.h:5896 note: c_enet.lib(c_enet.obj):(enet_deinitialize) error: lld-link: undefined symbol: __declspec(dllimport) timeBeginPeriod note: referenced by ...\Bind_ZPL_Enet_take2\enet\include\enet.h:5890 note: c_enet.lib(c_enet.obj):(enet_initialize) error: lld-link: undefined symbol: __declspec(dllimport) htonl note: referenced by ...\Bind_ZPL_Enet_take2\enet\include\enet.h:1557 note: c_enet.lib(c_enet.obj):(enet_crc32) note: referenced by ...\Bind_ZPL_Enet_take2\enet\include\enet.h:5020 note: c_enet.lib(c_enet.obj):(enet_host_bandwidth_throttle) note: referenced by ...\Bind_ZPL_Enet_take2\enet\include\enet.h:5023 note: c_enet.lib(c_enet.obj):(enet_host_bandwidth_throttle) note: referenced 27 more times

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So maybe that would help

hollow saffron Jul 26, 2025, 5:24 AM

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those look like windows APIs I think

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I don't remember which of the main 4 DLLs has which windows APIs in it

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but sounds like you'll need to link that

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WSAStartup is winsock, not sure which DLL that's in

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timeBeginPeriod is in Winmm.lib

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I google "WSAStartup dll" and get this MSDN article:
https://learn.microsoft.com/en-us/windows/win32/api/winsock/nf-winsock-wsastartup

at the bottom it says this:

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and that's how I figure out which DLL each windows API is in

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so yeah, sounds like you need to link those. I haven't done that yet, so not sure how to do that. probably isn't difficult tho

mint pivot Jul 26, 2025, 5:30 AM

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Okay I will look into that. Thank you

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I think I will call it quits for the time being and I will take a look at this later. I appreciate all the help

hollow saffron Jul 26, 2025, 6:06 AM

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I guess it's as simple as exe.linkSystemLibrary("ws2_32") etc.
https://ziggit.dev/t/msvc-linking-woes/9475/3

Ziggit

MSVC linking woes

If you were calling “closesocket” from zig, you’d call an extern function that declares it comes from the “ws2_32” library (see ws2_32.zig). Since C doesn’t have a mechanism to tie functions to the library they come from, you have to manually specify these libraries yourself. So in general, there are many functions provided by buil...

mint pivot Jul 26, 2025, 6:09 AM

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Okay I think it is working now

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To any unfortunate soul who has the same problem I had to link c_enet.linkSystemLibrary("ws2_32"); c_enet.linkSystemLibrary("winmm");

mint pivot Jul 26, 2025, 6:09 AM

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hollow saffron I guess it's as simple as `exe.linkSystemLibrary("ws2_32")` etc. https://ziggit....

Thanks again; your help has been greatly appreciated

mint pivot Jul 26, 2025, 6:25 AM

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hollow saffron I guess it's as simple as `exe.linkSystemLibrary("ws2_32")` etc. https://ziggit....

Can I ask what Hexeditor you would recommend? I am seeing if I can fix the file that was generated by translate-c

hollow saffron Jul 26, 2025, 6:27 AM

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imhex is free, it's not bad

mint pivot Jul 26, 2025, 6:40 AM

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hollow saffron imhex is free, it's not bad

Ok, how do you remove the BOM?

hollow saffron Jul 26, 2025, 6:42 AM

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select the first two characters and do file -> remove. I think you might be able to use backspace too, not sure

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if it doesn't say FFEF or whatever, it's not a BOM

mint pivot Jul 26, 2025, 6:44 AM

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Again, I am endebted

mint pivot Jul 26, 2025, 6:46 AM

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hollow saffron if it doesn't say FFEF or whatever, it's not a BOM

Alright, here is a riddle for you. I deleted the BOM and then re-ran by build script, and the BOM was back.

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Nevermi- y'know I think I'll try to figure this one out on my own. It seems to be inconsistent.

hollow saffron Jul 26, 2025, 6:48 AM

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maybe it's coming from your .h file

mint pivot Jul 26, 2025, 6:48 AM

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hollow saffron maybe it's coming from your .h file

hmmm; that would be unideal.

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Any idea how I might fix that?

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The error is now : "raw_enet.zig:1:2: error: expected ',' after field
p"

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but you have already helped me so much. If you want to do something else, I get it

hollow saffron Jul 26, 2025, 6:52 AM

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if it's coming from the .h file, try opening the .h file in the hex editor

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I'm playing metal gear solid rn heh

mint pivot Jul 26, 2025, 6:54 AM

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The 1st 3 Bytes are 2F 2A 2A

mint pivot Jul 26, 2025, 6:55 AM

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hollow saffron if it's coming from the .h file, try opening the .h file in the hex editor

So I don't think it has a BOM

hollow saffron Jul 26, 2025, 6:56 AM

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it shows on the right what those correspond to

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/** sounds like it starts with a comment, and not a BOM

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so that's not it

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dunno why it's inserting a BOM

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here's something related:
https://stackoverflow.com/a/2554498

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I wonder if you have some weird plugin or vscode setting that is saving a BOM automatically somehow

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dunno what that would be tho

mint pivot Jul 26, 2025, 7:00 AM

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That worked

mint pivot Aug 3, 2025, 3:22 AM

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hollow saffron it shows on the right what those correspond to

Hey, I just wanted to say that I found that ZPL wasn't the version that I was looking for ( I am trying to follow along with a tutorial and I ran into some issues ) so I switched back to the base version and, by looking back at the help you have given here I managed to get that working (I had another BOM from the translate Zig-file), so, in short, I just wanted to say thank you again for your help. I really appreciate it.

#Zig Use Single .h File