diff --git a/src/ffi.md b/src/ffi.md index 8d1a882..684e712 100644 --- a/src/ffi.md +++ b/src/ffi.md @@ -721,17 +721,20 @@ No `transmute` required! ## FFI and unwinding -It’s important to be mindful of unwinding when working with FFI. Each -non-`Rust` ABI comes in two variants, one with `-unwind` suffix and one without. If -you expect Rust `panic`s or foreign (e.g. C++) exceptions to cross an FFI -boundary, that boundary must use the appropriate `-unwind` ABI string (note -that compiling with `panic=abort` will still cause `panic!` to immediately -abort the process, regardless of which ABI is specified by the function that -`panic`s). +It’s important to be mindful of unwinding when working with FFI. Most +ABI strings come in two variants, one with an `-unwind` suffix and one without. +The `Rust` ABI always permits unwinding, so there is no `Rust-unwind` ABI. +If you expect Rust `panic`s or foreign (e.g. C++) exceptions to cross an FFI +boundary, that boundary must use the appropriate `-unwind` ABI string. Conversely, if you do not expect unwinding to cross an ABI boundary, use one of -the non-`unwind` ABI strings (other than `Rust`, which always permits -unwinding). If an unwinding operation does encounter an ABI boundary that is +the non-`unwind` ABI strings. + +> Note: Compiling with `panic=abort` will still cause `panic!` to immediately +abort the process, regardless of which ABI is specified by the function that +`panic`s. + +If an unwinding operation does encounter an ABI boundary that is not permitted to unwind, the behavior depends on the source of the unwinding (Rust `panic` or a foreign exception):