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Reference / Ffi

Borrow

finalclass
final class Borrow

Parameter attribute: the caller keeps ownership of the pointer and the callee must not free it.

The ownership attributes (Borrow, BorrowMut, Take, Give, StaticPtr) document who owns a pointer across an FFI call. They are checked at compile time, not lowered: nothing is freed on your behalf. They require a {@see Symbol} on the same declaration, apply only to pointer-carrying parameters or returns, and Give and StaticPtr exclude each other. At most one of Borrow, BorrowMut and Take may sit on a parameter. Take on a string and Give on a string return are rejected, because a PHP string is reference counted and must never reach C's free().

#[Library('c'), Symbol('strlen')]
function strlen(#[Borrow] string $s): int { return 0; }

See also: Symbol

Methods

__construct()Create the attribute.

__construct()#source

function __construct(public ?string $lifetime = null)

Create the attribute.

Parameters

$lifetime string|null = null
optional lifetime label for documentation; it is not checked

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