Enum Env 

pub enum Env {
    None,
    Gnu,
    Musl,
    Msvc,
    Android,
    Simulator,
    MacAbi,
}

The environment component of a tuple.

For Linux this is the C library, and it is the field that decides the syscall wrappers, the start files, the symbol versions and whether a static link is supported. For Darwin it is the ABI variant, simulator or Mac Catalyst, which is not a libc at all. For Windows it is both at once: gnu means mingw-w64 and msvcrt, msvc means the Microsoft SDK and the universal CRT, and the two produce different object code for the same source.

One field carrying two meanings is not ideal, and it is what every existing toolchain does, so a tuple that spelled it differently would not round-trip through the tools everyone else uses. spec/cross-compile/03-target-model.md section 3.5 takes the compatibility.

Variants

None

No environment component. Darwin, the BSDs, illumos, WASI and freestanding.

Gnu

glibc. Versioned, and the version is load bearing: spec/cross-compile/09-libc-stubs.md is mostly about the fact that a symbol here has a version node attached to it.

Musl

musl. The default for static linking and the first cross target, because it is one tarball with no version nodes and no abilist.

Msvc

The Microsoft toolchain: the Windows SDK headers and the universal CRT.

Android

Bionic. A Linux kernel with an API level instead of a libc version.

Simulator

A Darwin simulator ABI. Same architecture as the host, different platform value in LC_BUILD_VERSION, different SDK.

MacAbi

Mac Catalyst. An iOS ABI hosted on macOS.

Implementations

impl Env

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

The canonical name, without the version and without any ABI suffix.

The suffixes that GCC fuses into this component, eabihf on ARM and x32 on x86-64, are not here. They come from the ABI and the data model, and crate::TargetTuple puts them back when it formats the tuple. Storing them here as well would be the same fact in two places, which is the shape of every bug where a target is configured half one way.

pub const fn is_libc(self) -> bool

Whether this environment is a C library whose version the tuple may pin.

pub const fn supports_static_link(self) -> bool

Whether a fully static link is supported.

glibc technically permits one and it is a trap: dlopen, NSS and iconv all stop working, quietly, at run time on the user’s machine rather than at link time on ours. spec/cross-compile/10-runtime.md section 10.6 says the driver warns instead of refusing, because a program that uses none of those three is fine and it is not our place to say which.

pub const fn version_is_api_level(self) -> bool

Whether a version attached to this environment is an API level rather than a release number, which changes how it is compared and how the stub set is chosen.

Trait Implementations

impl Clone for Env

fn clone(&self) -> Env

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Copy for Env

impl Debug for Env

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

Formats the value using the given formatter.

impl Default for Env

fn default() -> Env

Returns the “default value” for a type.

impl Display for Env

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

Formats the value using the given formatter.

impl Eq for Env

impl Hash for Env

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 Ord for Env

fn cmp(&self, other: &Env) -> 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.

fn clamp_to<R>(self, range: R) -> Self

where Self: Sized, R: ClampBounds<Self>,

🔬This is a nightly-only experimental API. (clamp_to)

Restrict a value to a certain range.

impl PartialEq for Env

fn eq(&self, other: &Env) -> bool

Equality operator ==.

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

Inequality operator !=.

impl PartialOrd for Env

fn partial_cmp(&self, other: &Env) -> 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 StructuralPartialEq for Env