// until C++20 bool operator<(const_reference lhs, const_reference rhs) noexcept; // (1) template<typename ScalarType> bool operator<(const_reference lhs, const ScalarType rhs) noexcept; // (2) template<typename ScalarType> bool operator<(ScalarType lhs, const const_reference rhs) noexcept; // (2)
Compares whether one JSON value lhs
is less than another JSON value rhs
according to the following rules:
#!cpp false
.operator<
.lhs
and rhs
have different types, the values are ignored and the order of the types is considered, which is:Compares wether a JSON value is less than a scalar or a scalar is less than a JSON value by converting the scalar to a JSON value and comparing both JSON values according to 1.
ScalarType
: a scalar type according to std::is_scalar<ScalarType>::value
lhs
(in) : first value to consider
rhs
(in) : second value to consider
whether lhs
is less than rhs
No-throw guarantee: this function never throws exceptions.
Linear.
!!! note “Comparing NaN
”
`NaN` values are unordered within the domain of numbers. The following comparisons all yield `#!cpp false`: 1. Comparing a `NaN` with itself. 2. Comparing a `NaN` with another `NaN`. 3. Comparing a `NaN` and any other number.
!!! note “Operator overload resolution”
Since C++20 overload resolution will consider the _rewritten candidate_ generated from [`operator<=>`](operator_spaceship.md).
??? example
The example demonstrates comparing several JSON types. ```cpp --8<-- "examples/operator__less.cpp" ``` Output: ```json --8<-- "examples/operator__less.output" ```