int64

Property	Value
Size	8 bytes (64 bits)
Minimum value	−263 ≈ −9.223372 × 1018
Maximum value	263−1 ≈ 9.223372 × 1018
Literal suffix	i64
Representation	Two's complement
Hardware support	Native on all supported targets

int64 is a full-width signed integer matching the native word of 64-bit targets — a fixed-width type whose size is identical on every target platform. Like all signed types it uses two's complement: the most significant bit is the sign bit, and the range is asymmetric (the minimum has no positive counterpart).

Literals

let a: int64 = -9000000000;  // explicit annotation
let b = 42i64;               // type suffix

If a literal value does not fit in int64, the compiler emits an error at compile time. See Literals for decimal, hexadecimal, octal, and binary forms.

Typical Use Cases

• Timestamps (nanoseconds since epoch)
• Memory offsets and sizes on 64-bit systems
• Database keys and large counters

Arithmetic

Operator	Description	Compound
+	Addition	+=
-	Subtraction	-=
*	Multiplication	*=
/	Division	/=
%	Remainder	%=
**	Exponentiation	n/a

let a: int64 = 10;
let b: int64 = 3;

let sum  = a + b;   // 13
let quot = a / b;   // 3   truncates toward zero
let rem  = a % b;   // 1   carries the sign of the dividend

Division and remainder truncate toward zero, so the remainder takes the sign of the dividend: -7 % 2 is -1.

Overflow. In debug builds, signed overflow raises a fatal error. In release builds it wraps modulo 2⁶⁴ in two's-complement fashion. Wraparound is well-defined in Rux (unlike C/C++), but relying on it is almost always a logic error.

Comparison

Operator	Description	Result
==	Equal	bool
!=	Not equal	bool
<	Less than	bool
<=	Less than or equal	bool
>	Greater than	bool
>=	Greater than or equal	bool

Both operands must have the same type. Comparing int64 with another integer type — or with an unsigned type such as uint64 — is a compile-time error; cast one operand explicitly first.

Shift and Bitwise

Right shift on a signed value is arithmetic: vacated bits are filled with the sign bit, preserving the sign.

let s: int64 = -8;
let r = s >> 2;    // -2   sign-filled (arithmetic) right shift

The bitwise operators &, |, ^, and ~ are also defined (~x equals −(x + 1)), but bitmask work usually reads more clearly on unsigned types.

Conversion

Rux performs no implicit numeric conversions — every conversion uses the as operator. Widening to a wider signed type preserves the value through sign extension; narrowing keeps only the low-order bits; a same-width signed↔unsigned cast reinterprets the bit pattern.

let x: int64 = -1;
let small = x as int32;   // -1                    narrowed, low 32 bits kept
let u     = x as uint64;  // 18446744073709551615  same width, bits reinterpreted

See Also

• uint64 — unsigned counterpart of the same width
• Unsigned Integer Types — the unsigned integer family