std::experimental::ranges::less
Defined in header <experimental/ranges/functional>
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template
<
class T =
void
>
requires StrictTotallyOrdered<T>
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(ranges TS) | |
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template
<>
struct less< void > ; |
(ranges TS) | |
Function object for performing comparisons. The primary template invokes operator< on const lvalues of type T. The specialization less<void>
All specializations of less are Semiregular.
Member types
| Member type | Definition |
is_transparent (member only of less<void> specialization)
|
/* unspecified */ |
Member functions
operator() |
checks if the first argument is less than the second (public member function) |
std::experimental::ranges::less::operator()
|
constexpr
bool operator(
)
(
const T& x, const T& y)
const
;
|
(1) | (member only of primary less<T> template) |
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template
<
class T, class U >
requires StrictTotallyOrderedWith<T, U>
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(2) | (member only of less<void> specialization) |
t and u. Equivalent to
return
std::forward
<T>
(t)
<
std::forward
<U>
(u)
;
, except when that expression resolves to a call to a builtin operator<
When a call to (1) or (2) would invoke a built-in operator comparing pointers of type P, the result is instead determined as follows:
- Returns
true
if the (possibly converted) value of the first argument precedes the (possibly converted) value of the second argument in the implementation-defined strict total ordering over all pointer values of type
P. This strict total ordering is consistent with the partial order imposed by the builtin operators<,>,<=, and>= - Otherwise, returns false.
The behavior is undefined unless the conversion sequences from both T and U to P are equality-preserving (see below).
Equality preservation
An expression is equality preserving if it results in equal outputs given equal inputs.
- The inputs to an expression consist of its operands.
- The outputs of an expression consist of its result and all operands modified by the expression (if any).
Every expression required to be equality preserving is further required to be stable
Notes
Unlike std::less, ranges::less requires all six comparison operators <, <=, >, >=, == and != to be valid (via the StrictTotallyOrdered and StrictTotallyOrderedWith
Example
| This section is incomplete Reason: no example |
See also
| function object implementing x < y (class template) |