Operators

There is no operator overloading. When you see an operator in Zig, you know that it is doing something from below, and nothing else.

Addition

syntax

zig

a + b
a += b

Can cause overflow for integers.
Invokes Peer Type Resolution for the operands.
See also @addWithOverflow.

example

zig

2 + 5 == 7

Wrapping Addition

syntax

zig

a +% b
a +%= b

Twos-complement wrapping behavior.
Invokes Peer Type Resolution for the operands.
See also @addWithOverflow.

example

zig

@as(u32, 0xffffffff) +% 1 == 0

Saturating Addition

syntax

zig

a +| b
a +|= b

Invokes Peer Type Resolution for the operands.

example

zig

@as(u8, 255) +| 1 == @as(u8, 255)

Subtraction

syntax

zig

a - b
a -= b

Can cause overflow for integers.
Invokes Peer Type Resolution for the operands.
See also @subWithOverflow.

example

zig

2 - 5 == -3

Wrapping Subtraction

syntax

zig

a -% b
a -%= b

Twos-complement wrapping behavior.
Invokes Peer Type Resolution for the operands.
See also @subWithOverflow.

example

zig

@as(u8, 0) -% 1 == 255

Saturating Subtraction

syntax

zig

a -| b
a -|= b

Invokes Peer Type Resolution for the operands.

example

zig

@as(u32, 0) -| 1 == 0

Negation

syntax

zig

-a

Can cause overflow for integers.

example

zig

-1 == 0 - 1

Wrapping Negation

syntax

zig

-%a

Twos-complement wrapping behavior.

example

zig

-%@as(i8, -128) == -128

Multiplication

syntax

zig

a * b
a *= b

Can cause overflow for integers.
Invokes Peer Type Resolution for the operands.
See also @mulWithOverflow.

example

zig

2 * 5 == 10

Wrapping Multiplication

syntax

zig

a *% b
a *%= b

Twos-complement wrapping behavior.
Invokes Peer Type Resolution for the operands.
See also @mulWithOverflow.

example

zig

@as(u8, 200) *% 2 == 144

Saturating Multiplication

syntax

zig

a *| b
a *|= b

Invokes Peer Type Resolution for the operands.

example

zig

@as(u8, 200) *| 2 == 255

Division

syntax

zig

a / b
a /= b

Can cause overflow for integers.
Can cause Division by Zero for integers.
Can cause Division by Zero for floats in FloatMode.Optimized Mode.
Signed integer operands must be comptime-known and positive.
In other cases, use @divTrunc, @divFloor, or @divExact instead.
Invokes Peer Type Resolution for the operands.

example

zig

10 / 5 == 2

Remainder Division

syntax

zig

a % b
a %= b

Can cause Division by Zero for integers.
Can cause Division by Zero for floats in FloatMode.Optimized Mode.
Signed or floating-point operands must be comptime-known and positive. In other cases, use @rem or @mod instead.
Invokes Peer Type Resolution for the operands.

example

zig

10 % 3 == 1

Bit Shift Left

syntax

zig

a << b
a <<= b

Moves all bits to the left, inserting new zeroes at the least-significant bit.
b must be comptime-known or have a type with log2 number of bits as a.
See also @shlExact.
See also @shlWithOverflow.

example

zig

0b1 << 8 == 0b100000000

Saturating Bit Shift Left

syntax

zig

a <<| b
a <<|= b

See also @shlExact.
See also @shlWithOverflow.

example

zig

@as(u8, 1) <<| 8 == 255

Bit Shift Right

syntax

zig

a >> b
a >>= b

Moves all bits to the right, inserting zeroes at the most-significant bit.
b must be comptime-known or have a type with log2 number of bits as a.
See also @shrExact.

example

zig

0b1010 >> 1 == 0b101

Bitwise And

syntax

zig

a & b
a &= b

Invokes Peer Type Resolution for the operands.

example

zig

0b011 & 0b101 == 0b001

Bitwise Or

syntax

zig

a | b
a |= b

Invokes Peer Type Resolution for the operands.

example

zig

0b010 | 0b100 == 0b110

Bitwise Xor

syntax

zig

a ^ b
a ^= b

Invokes Peer Type Resolution for the operands.

example

zig

0b011 ^ 0b101 == 0b110

Bitwise Not

syntax

zig

~a

example

zig

~@as(u8, 0b10101111) == 0b01010000

Defaulting Optional Unwrap

syntax

zig

a orelse b

If a is null, returns b ("default value"), otherwise returns the unwrapped value of a. Note that b may be a value of type noreturn.

example

zig

const value: ?u32 = null;
const unwrapped = value orelse 1234;
unwrapped == 1234

Optional Unwrap

syntax

zig

a.?

Equivalent to: a orelse unreachable

example

zig

const value: ?u32 = 5678;
value.? == 5678

Defaulting Error Unwrap

syntax

zig

a catch b
a catch |err| b

If a is an error, returns b ("default value"), otherwise returns the unwrapped value of a. Note that b may be a value of type noreturn. err is the error and is in scope of the expression b.

example

zig

const value: anyerror!u32 = error.Broken;
const unwrapped = value catch 1234;
unwrapped == 1234

Logical And

syntax

zig

a and b

If a is false, returns false without evaluating b. Otherwise, returns b.

example

zig

(false and true) == false

Logical Or

syntax

zig

a or b

If a is true, returns true without evaluating b. Otherwise, returns b.

example

zig

(false or true) == true

Boolean Not

syntax

zig

!a

example

zig

!false == true

Equality

syntax

zig

a == b

Returns true if a and b are equal, otherwise returns false.
Invokes Peer Type Resolution for the operands.

example

zig

(1 == 1) == true

Null Check

syntax

zig

a == null

Returns true if a is null, otherwise returns false.

example

zig

const value: ?u32 = null;
(value == null) == true

Inequality

syntax

zig

a != b

Returns false if a and b are equal, otherwise returns true. Invokes Peer Type Resolution for the operands.

example

zig

(1 != 1) == false

Non-Null Check

syntax

zig

a != null

Returns false if a is null, otherwise returns true.

example

zig

const value: ?u32 = null;
(value != null) == false

Greater Than

syntax

zig

a > b

Returns true if a is greater than b, otherwise returns false. Invokes Peer Type Resolution for the operands.

example

zig

(2 > 1) == true

Greater or Equal

syntax

zig

a >= b

Returns true if a is greater than or equal to b, otherwise returns false. Invokes Peer Type Resolution for the operands.

example

zig

(2 >= 1) == true

Less Than

syntax

zig

a < b

Returns true if a is less than b, otherwise returns false. Invokes Peer Type Resolution for the operands.

example

zig

(1 < 2) == true

Lesser or Equal

syntax

zig

a <= b

Returns true if a is less than or equal to b, otherwise returns false. Invokes Peer Type Resolution for the operands.

example

zig

(1 <= 2) == true

Array Concatenation

syntax

zig

a ++ b

Only available when the lengths of both a and b are compile-time known.

example

zig

const mem = @import("std").mem;
const array1 = [_]u32{1,2};
const array2 = [_]u32{3,4};
const together = array1 ++ array2;
mem.eql(u32, &together, &[_]u32{1,2,3,4})

Array Multiplication

syntax

zig

a ** b

Only available when the length of a and b are compile-time known.

example

zig

const mem = @import("std").mem;
const pattern = "ab" ** 3;
mem.eql(u8, pattern, "ababab")

Pointer Dereference

syntax

zig

a.*

example

zig

const x: u32 = 1234;
const ptr = &x;
ptr.* == 1234

Address Of

syntax

zig

&a

example

zig

const x: u32 = 1234;
const ptr = &x;
ptr.* == 1234

Error Set Merge

syntax

zig

a || b

example

zig

const A = error{One};
const B = error{Two};
(A || B) == error{One, Two}

Precedence

zig

x() x[] x.y x.* x.?
a!b
x{}
!x -x -%x ~x &x ?x
* / % ** *% *| ||
+ - ++ +% -% +| -|
<< >> <<|
& ^ | orelse catch
== != < > <= >=
and
or
= *= *%= *|= /= %= += +%= +|= -= -%= -|= <<= <<|= >>= &= ^= |=

Operators ​

Addition ​

Wrapping Addition ​

Saturating Addition ​

Subtraction ​

Wrapping Subtraction ​

Saturating Subtraction ​

Negation ​

Wrapping Negation ​

Multiplication ​

Wrapping Multiplication ​

Saturating Multiplication ​

Division ​

Remainder Division ​

Bit Shift Left ​

Saturating Bit Shift Left ​

Bit Shift Right ​

Bitwise And ​

Bitwise Or ​

Bitwise Xor ​

Bitwise Not ​

Defaulting Optional Unwrap ​

Optional Unwrap ​

Defaulting Error Unwrap ​

Logical And ​

Logical Or ​

Boolean Not ​

Equality ​

Null Check ​

Inequality ​

Non-Null Check ​

Greater Than ​

Greater or Equal ​

Less Than ​

Lesser or Equal ​

Array Concatenation ​

Array Multiplication ​

Pointer Dereference ​

Address Of ​

Error Set Merge ​

Precedence ​

Operators

Addition

Wrapping Addition

Saturating Addition

Subtraction

Wrapping Subtraction

Saturating Subtraction

Negation

Wrapping Negation

Multiplication

Wrapping Multiplication

Saturating Multiplication

Division

Remainder Division

Bit Shift Left

Saturating Bit Shift Left

Bit Shift Right

Bitwise And

Bitwise Or

Bitwise Xor

Bitwise Not

Defaulting Optional Unwrap

Optional Unwrap

Defaulting Error Unwrap

Logical And

Logical Or

Boolean Not

Equality

Null Check

Inequality

Non-Null Check

Greater Than

Greater or Equal

Less Than

Lesser or Equal

Array Concatenation

Array Multiplication

Pointer Dereference

Address Of

Error Set Merge

Precedence