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Diffstat (limited to 'compiler/rustc_error_codes/src/error_codes/E0756.md')
-rw-r--r-- | compiler/rustc_error_codes/src/error_codes/E0756.md | 29 |
1 files changed, 29 insertions, 0 deletions
diff --git a/compiler/rustc_error_codes/src/error_codes/E0756.md b/compiler/rustc_error_codes/src/error_codes/E0756.md new file mode 100644 index 000000000..ffdc421aa --- /dev/null +++ b/compiler/rustc_error_codes/src/error_codes/E0756.md @@ -0,0 +1,29 @@ +The `ffi_const` attribute was used on something other than a foreign function +declaration. + +Erroneous code example: + +```compile_fail,E0756 +#![feature(ffi_const)] + +#[ffi_const] // error! +pub fn foo() {} +# fn main() {} +``` + +The `ffi_const` attribute can only be used on foreign function declarations +which have no side effects except for their return value: + +``` +#![feature(ffi_const)] + +extern "C" { + #[ffi_const] // ok! + pub fn strlen(s: *const i8) -> i32; +} +# fn main() {} +``` + +You can get more information about it in the [unstable Rust Book]. + +[unstable Rust Book]: https://doc.rust-lang.org/nightly/unstable-book/language-features/ffi-const.html |