`<xstd/bits/bit/shl.hpp>`¶

This page also specifies <xstd/bits/bit/shr.hpp>, whose functions share this text.

`xstd::shl`, `xstd::shr`¶

// (1)
template<class X, integer S>
    requires see below
  constexpr auto shl(X x, S s) noexcept(see below) -> X;

// (2)
template<class X, integer S>
    requires see below
  constexpr auto shr(X x, S s) noexcept(see below) -> X;

Shift a set's keys by any count of any integer type, as P3793R2's shl and shr shift an integer's bits. They are the total forms beside the set's own << and >>, which at a static width take a count below the width as their precondition, as an integer's built-in shifts do.

shl moves every key s positions up.
shr moves every key s positions down.

Parameters¶

Parameter	Meaning
`x`	the set to shift
`s`	the count to shift by, which may be negative

Constraints: X is a set of this library that owns its keys, basic_bit_fixed_set, basic_bit_inplace_set, basic_bit_set or a type built on them, and S models integer, signed or unsigned, of any width.

Return value¶

Returns: x with each key at position p moved to position p + s, a key landing outside the positions the set can hold dropped.
Returns: x with each key at position p moved to position p - s, a key landing outside the positions the set can hold dropped.

Exceptions¶

As the set's own <<= and >>=: noexcept at a static width and an inplace capacity, and otherwise whatever growing the storage throws.

Notes¶

Every value of S is in the domain. A count whose magnitude is the width or more empties a set of static width; a set of run-time width grows towards max_size() and empties past it, as its <<= does.
A negative count shifts the other way, so shr(x, s) equals shl(x, -s) wherever -s is representable.
The count's type changes nothing but which counts it can hold.
A call is a constant expression.

<xstd/bits/bit/shl.hpp>¶

xstd::shl, xstd::shr¶