Struct

class Struct

use ffi::types::{Struct};

FFI tag for a C struct passed or returned by value.

Not written directly: name an extern struct type in declare instead, and the compiler uses this tag with that struct’s layout. A returned struct becomes a record whose fields are read with .name.

Examples#

use ffi::{dload, declare, invoke};
use ffi::types::{Int32};

extern struct Point {
    x: int32,
    y: int32,
};

let make_id = declare(lib, "make_point", (Int32, Int32), Point)?;
let p = invoke(lib, make_id, (3, 4))?;
let sum = p.x + p.y; // 7

See also#

• Int: FFI tag for a 64-bit signed integer (int64_t), passed from and returned as int.
• Float: FFI tag for a 64-bit float (double), passed from and returned as float.
• String: FFI tag for a NUL-terminated C string (const char *), passed from and returned as string.
• Void: FFI tag for no value (void), valid only as a return type.
• Bool: FFI tag for a C bool (one byte, 0 or 1), passed from and returned as bool.
• Int8: FFI tag for an 8-bit signed integer (int8_t), passed from and returned as int.
• Int16: FFI tag for a 16-bit signed integer (int16_t), passed from and returned as int.
• Int32: FFI tag for a 32-bit signed integer (int32_t), passed from and returned as int.