Enum ExternAbi

pub enum ExternAbi {
    C {
        unwind: bool,
    },
    System {
        unwind: bool,
    },
    Rust,
    RustCall,
    RustCold,
    RustInvalid,
    Unadjusted,
    Custom,
    EfiApi,
    Aapcs {
        unwind: bool,
    },
    CmseNonSecureCall,
    CmseNonSecureEntry,
    GpuKernel,
    PtxKernel,
    AvrInterrupt,
    AvrNonBlockingInterrupt,
    Msp430Interrupt,
    RiscvInterruptM,
    RiscvInterruptS,
    X86Interrupt,
    Cdecl {
        unwind: bool,
    },
    Stdcall {
        unwind: bool,
    },
    Fastcall {
        unwind: bool,
    },
    Thiscall {
        unwind: bool,
    },
    Vectorcall {
        unwind: bool,
    },
    SysV64 {
        unwind: bool,
    },
    Win64 {
        unwind: bool,
    },
}

ABI we expect to see within extern "{abi}"

Variants

C

presumed C ABI for the platform

Fields

unwind: bool

System

ABI of the “system” interface, e.g. the Win32 API, always “aliasing”

Fields

unwind: bool

Rust

that’s us!

RustCall

the mostly-unused unboxed_closures ABI, effectively now an impl detail unless someone puts in the work to make it viable again… but would we need a special ABI?

RustCold

For things unlikely to be called, where reducing register pressure in extern "Rust" callers is worth paying extra cost in the callee. Stronger than just #[cold] because fn pointers might be incompatible.

RustInvalid

An always-invalid ABI that’s used to test “this ABI is not supported by this platform” in a platform-agnostic way.

Unadjusted

Unstable impl detail that directly uses Rust types to describe the ABI to LLVM. Even normally-compatible Rust types can become ABI-incompatible with this ABI!

Custom

An ABI that rustc does not know how to call or define. Functions with this ABI can only be created using #[naked] functions or extern "custom" blocks, and can only be called from inline assembly.

EfiApi

UEFI ABI, usually an alias of C, but sometimes an arch-specific alias and only valid on platforms that have a UEFI standard

Aapcs

Arm Architecture Procedure Call Standard, sometimes ExternAbi::C is an alias for this

Fields

unwind: bool

CmseNonSecureCall

extremely constrained barely-C ABI for TrustZone

CmseNonSecureEntry

extremely constrained barely-C ABI for TrustZone

GpuKernel

An entry-point function called by the GPU’s host

PtxKernel

An entry-point function called by the GPU’s host

AvrInterrupt

AvrNonBlockingInterrupt

Msp430Interrupt

RiscvInterruptM

RiscvInterruptS

X86Interrupt

Cdecl

ExternAbi::C but spelled funny because x86

Fields

unwind: bool

Stdcall

gnu-stdcall on “unix” and win-stdcall on “windows”

Fields

unwind: bool

Fastcall

gnu-fastcall on “unix” and win-fastcall on “windows”

Fields

unwind: bool

Thiscall

windows C++ ABI

Fields

unwind: bool

Vectorcall

uses AVX and stuff

Fields

unwind: bool

SysV64

Fields

unwind: bool

Win64

Fields

unwind: bool

Implementations

impl ExternAbi

pub const ALL_VARIANTS: &[Self]

pub const fn as_str(&self) -> &'static str

impl ExternAbi

pub fn is_rustic_abi(self) -> bool

An ABI “like Rust”

These ABIs are fully controlled by the Rust compiler, which means they

• support unwinding with -Cpanic=unwind, unlike extern "C"
• often diverge from the C ABI
• are subject to change between compiler versions

pub fn supports_varargs(self) -> bool

impl ExternAbi

pub const FALLBACK: ExternAbi

Default ABI chosen for extern fn declarations without an explicit ABI.

pub fn name(self) -> &'static str

Trait Implementations

impl Clone for ExternAbi

fn clone(&self) -> ExternAbi

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for ExternAbi

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl<__D: SpanDecoder> Decodable<__D> for ExternAbi

fn decode(__decoder: &mut __D) -> Self

impl Display for ExternAbi

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl<__E: SpanEncoder> Encodable<__E> for ExternAbi

fn encode(&self, __encoder: &mut __E)

impl FromStr for ExternAbi

type Err = AbiFromStrErr

The associated error which can be returned from parsing.

fn from_str(s: &str) -> Result<ExternAbi, Self::Err>

Parses a string s to return a value of this type.

impl Hash for ExternAbi

fn hash<H: Hasher>(&self, state: &mut H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl<C> HashStable<C> for ExternAbi

fn hash_stable(&self, _: &mut C, hasher: &mut StableHasher)

impl Ord for ExternAbi

fn cmp(&self, rhs: &Self) -> Ordering

This method returns an Ordering between self and other.

fn max(self, other: Self) -> Self

where Self: Sized,

Compares and returns the maximum of two values.

fn min(self, other: Self) -> Self

where Self: Sized,

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Self

where Self: Sized,

Restrict a value to a certain interval.

impl PartialEq for ExternAbi

fn eq(&self, rhs: &Self) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl PartialOrd for ExternAbi

fn partial_cmp(&self, rhs: &Self) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

fn lt(&self, other: &Rhs) -> bool

Tests less than (for self and other) and is used by the < operator.

fn le(&self, other: &Rhs) -> bool

Tests less than or equal to (for self and other) and is used by the <= operator.

fn gt(&self, other: &Rhs) -> bool

Tests greater than (for self and other) and is used by the > operator.

fn ge(&self, other: &Rhs) -> bool

Tests greater than or equal to (for self and other) and is used by the >= operator.

impl StableOrd for ExternAbi

const CAN_USE_UNSTABLE_SORT: bool = true

const THIS_IMPLEMENTATION_HAS_BEEN_TRIPLE_CHECKED: () = ()

Marker to ensure that implementors have carefully considered whether their Ord implementation obeys this trait’s contract.

impl Copy for ExternAbi

impl Eq for ExternAbi

Layout

Note: Most layout information is completely unstable and may even differ between compilations. The only exception is types with certain repr(...) attributes. Please see the Rust Reference's “Type Layout” chapter for details on type layout guarantees.

Size: 2 bytes

Size for each variant:

• C: 1 byte
• System: 1 byte
• Rust: 0 bytes
• RustCall: 0 bytes
• RustCold: 0 bytes
• RustInvalid: 0 bytes
• Unadjusted: 0 bytes
• Custom: 0 bytes
• EfiApi: 0 bytes
• Aapcs: 1 byte
• CmseNonSecureCall: 0 bytes
• CmseNonSecureEntry: 0 bytes
• GpuKernel: 0 bytes
• PtxKernel: 0 bytes
• AvrInterrupt: 0 bytes
• AvrNonBlockingInterrupt: 0 bytes
• Msp430Interrupt: 0 bytes
• RiscvInterruptM: 0 bytes
• RiscvInterruptS: 0 bytes
• X86Interrupt: 0 bytes
• Cdecl: 1 byte
• Stdcall: 1 byte
• Fastcall: 1 byte
• Thiscall: 1 byte
• Vectorcall: 1 byte
• SysV64: 1 byte
• Win64: 1 byte