[expr.shift]

# 7 Expressions [[expr]](./#expr)

## 7.6 Compound expressions [[expr.compound]](expr.compound#expr.shift)

### 7.6.7 Shift operators [expr.shift]

[1](#1)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/expressions.tex#L7230)

The shift operators << and >> group left-to-right[.](#1.sentence-1)

[shift-expression:](#nt:shift-expression "7.6.7 Shift operators [expr.shift]")  
[*additive-expression*](expr.add#nt:additive-expression "7.6.6 Additive operators [expr.add]")  
[*shift-expression*](#nt:shift-expression "7.6.7 Shift operators [expr.shift]") << [*additive-expression*](expr.add#nt:additive-expression "7.6.6 Additive operators [expr.add]")  
[*shift-expression*](#nt:shift-expression "7.6.7 Shift operators [expr.shift]") >> [*additive-expression*](expr.add#nt:additive-expression "7.6.6 Additive operators [expr.add]")

The operands shall be prvalues of integral or unscoped enumeration type and integral
promotions are performed[.](#1.sentence-2)

The type of the result is that of the promoted
left operand[.](#1.sentence-3)

The behavior is undefined if the right operand is negative, or greater
than or equal to the width of the promoted left operand[.](#1.sentence-4)

[2](#2)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/expressions.tex#L7258)

The value of E1 << E2 is the unique value congruent toE1×2E2 modulo 2N,
where N is the width of the type of the result[.](#2.sentence-1)

[*Note [1](#note-1)*:

E1 is left-shifted E2 bit positions;
vacated bits are zero-filled[.](#2.sentence-2)

— *end note*]

[3](#3)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/expressions.tex#L7267)

The value of E1 >> E2 is E1/2E2,
rounded towards negative infinity[.](#3.sentence-1)

[*Note [2](#note-2)*:

E1 is right-shifted E2 bit positions[.](#3.sentence-2)

Right-shift on signed integral types is an arithmetic right shift,
which performs sign-extension[.](#3.sentence-3)

— *end note*]

[4](#4)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/expressions.tex#L7276)

The expression E1 is sequenced before the expression E2[.](#4.sentence-1)