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Comment by SkiFire13 | Hacker News Reader

Zig's tco support is not much different than Clang's `[[clang::musttail]]` in C++. Both have the big restriction that the two functions involved are required to have the same signature.

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> Both have the big restriction that the two functions involved are required to have the same signature.

I did not know that! But I am a bit confused, since I don't really program in either language. Where exactly in the documentation could I read more about this? Or see more examples?

The language reference for @call[0] was quite unhelpful for my untrained eye.

[0] https://ziglang.org/documentation/master/#call

Generally I also find Zig's documentation pretty lacking, instead I try looking for the relevant issues/prs. In this case I found comments on this issues [1] which seem to still hold true. That same issue also links to the relevant LLVM/Clang issue [2], and the same restriction is also being proposed for Rust [3]. This is were I first learned about it and prompted me to investigate whether Zig also suffers from the same issue.

[1]: https://github.com/ziglang/zig/issues/694#issuecomment-15674... [2]: https://github.com/llvm/llvm-project/issues/54964 [3]: https://github.com/rust-lang/rfcs/pull/3407

This limitation is to ensure that the two functions use the exact same calling convention (input & output registers, and values passed via stack). It can depend on the particular architecture.

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