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by j-james 1114 days ago
Yeah, I read through that: unless I'm missing something I think what I'm curious about is "calling C code from Zig and vice versa" in the to-be-written section.

Nim also has support for `ctypes` and compiles to C as its main target: yet though its interop is powerful it lacks in ergonomics, formerly you had to manually wrap every function you wished to use and this was only recently fixed by a macro-heavy external library.

I'm wondering what Zig does because IMO even if you have an excellent technical solution getting people to actually use it alongside C is hard, it has to be seamlessly seamless. Nim's C interop is rarely used outside of wrappers and it even more rarely is used to produce C libraries (though perhaps that's more a fault of incompatible type systems)
1 comments
TUSF 1114 days ago
With Zig, you just write something like:

  const c = @cImport({
      @cDefine("SOME_MACRO", "1");
      @cInclude("raylib.h");
  });
Which translates the header files directly into Zig and allows you to call into them under whatever namespace you assigned them under. You even get completions (assuming you're using the language server)
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j-james 1114 days ago
Right, but I'm curious about the calling-Zig-from-C interop, not the other way around.
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kmz42 1111 days ago
I was curious as well so I made a simple example to see how easy it is[0]

The documentation, especially for the build system, was lacking. But the interop itself is pretty smooth. Only rough point is that I can't define a struct type in Zig and use it in C; you HAVE to define your structs in C if you plan to pass them between the languages (as far as I know anyways).

Zig has documentation on making your Zig structs match the layout of C structs[1] so I assume the intended use case is not as I have done (use the C type in Zig) but instead of define a matching Zig type and cast your C structs into Zig structs, or vice versa, at the boundary between languages.

Structs aside, for functions you just stick "export" on the Zig functions to make them available at link time (presumably) and use "callconv(.C)" so C can call them cleanly. Very easy.

[0] https://github.com/kmz42/zig_c_interop_test

[1] https://ziglearn.org/chapter-4/#extern-structs

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