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Rework the definitions of the extern ABIs #2003

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Merged
merged 6 commits into from
Oct 8, 2025
Merged

Rework the definitions of the extern ABIs #2003

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4047870
Rework the definitions of the extern ABIs
ehuss Sep 17, 2025
e8969f7
Add more ABI correspondence with other compilers
ehuss Sep 29, 2025
a78b6c2
Clarify default when not using `extern fn`
traviscross Oct 8, 2025
5ef9f4f
Clarify about Windows functions with explicit ABI
traviscross Oct 8, 2025
45de0c5
Convert ABI "details" links to lists
traviscross Oct 8, 2025
cc463db
Strengthen wording on "C" ABI
traviscross Oct 8, 2025
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Strengthen wording on "C" ABI 
When using the "C" ABI, do we "match" the default ABI chosen by the dominant C compiler for the target or do we "attempt" to match it? Tough question. There are believed to be some exceptions in current behavior. However, in the Reference, we generally state things in terms of what the consensus is on how they should be and then note the bugs, so let's do that here. We'll just say that we "match" it.
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traviscross committed Oct 8, 2025
commit cc463db8aa2b19cef0a040da37e41634a3b1148f
2 changes: 1 addition & 1 deletion src/items/external-blocks.md
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Expand Up @@ -121,7 +121,7 @@ r[items.extern.abi.rust]
* `unsafe extern "Rust"` --- The native calling convention for Rust functions and closures. This is the default when a function is declared without using [`extern fn`]. The Rust ABI offers no stability guarantees.

r[items.extern.abi.c]
* `unsafe extern "C"` --- The "C" ABI attempts to match the default ABI chosen by the dominant C compiler for the target.
* `unsafe extern "C"` --- The "C" ABI matches the default ABI chosen by the dominant C compiler for the target.

r[items.extern.abi.system]
* `unsafe extern "system"` --- This is equivalent to `extern "C"` except on Windows x86_32 where it is equivalent to `"stdcall"`.
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