Enum Visibility 

pub enum Visibility {
    Default,
    Hidden,
    Protected,
}

How far outside a shared library a name reaches.

A different question from Binding and asked of a different linker. The binding is what the static linker does with a name while it is building the output, and this is what the dynamic linker may do with it once the output is a shared library and is being loaded. A hidden name is still global to the static link, so two files in the same library can call each other by it; it is simply not in the dynamic symbol table afterwards, so nothing outside can name it.

Written down here as its own thing rather than folded into the binding because it is the mistake tamnd/rucc#733 was: a writer that has one word for both ends up saying something about visibility while it thinks it is saying something about linkage, and what it said was hidden.

It means nothing for a Binding::Local name. static is already invisible to the whole world outside the file, and ELF records STV_DEFAULT for one, which is what gcc writes.

Variants

Default

In the dynamic symbol table, and a reference from inside the library may be satisfied by a definition somewhere else, which is what makes LD_PRELOAD work. What a name gets when nothing said otherwise.

Hidden

Not in the dynamic symbol table at all, so nothing outside the library can name it and every reference to it from inside binds here. __attribute__((visibility("hidden"))).

Protected

In the dynamic symbol table, so something outside can name it, but a reference from inside the library binds to the definition inside it and cannot be interposed.

Trait Implementations

impl Clone for Visibility

fn clone(&self) -> Visibility

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Copy for Visibility

impl Debug for Visibility

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

Formats the value using the given formatter.

impl Default for Visibility

fn default() -> Visibility

Returns the “default value” for a type.

impl Eq for Visibility

impl PartialEq for Visibility

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

Equality operator ==.

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

Inequality operator !=.

impl StructuralPartialEq for Visibility