json/docs/mkdocs/docs/api/json_pointer/operator_ne.md

nlohmann::json_pointer::operator!=

// until C++20
template<typename RefStringTypeLhs, typename RefStringTypeRhs>
bool operator!=(
    const json_pointer<RefStringTypeLhs>& lhs,
    const json_pointer<RefStringTypeRhs>& rhs) noexcept;  // (1)

template<typename RefStringTypeLhs, typename StringType>
bool operator!=(
    const json_pointer<RefStringTypeLhs>& lhs,
    const StringType& rhs);                               // (2)

template<typename RefStringTypeRhs, typename StringType>
bool operator!=(
    const StringType& lhs,
    const json_pointer<RefStringTypeRhs>& rhs);           // (2)

1. Compares two JSON pointers for inequality by comparing their reference tokens.

2. Compares a JSON pointer and a string or a string and a JSON pointer for inequality by converting the string to a JSON pointer and comparing the JSON pointers according to 1.

Template parameters

RefStringTypeLhs, RefStringTypeRhs

the string type of the left-hand side or right-hand side JSON pointer, respectively

StringType

the string type derived from the json_pointer operand (json_pointer::string_t)

Parameters

lhs (in)

first value to consider

rhs (in)

second value to consider

Return value

whether the values lhs/*this and rhs are not equal

Exception safety

1. No-throw guarantee: this function never throws exceptions.
2. Strong exception safety: if an exception occurs, the original value stays intact.

Exceptions

1. (none)
2. The function can throw the following exceptions:
   • Throws parse_error.107 if the given JSON pointer s is nonempty and does not begin with a slash (/); see example below.
   • Throws parse_error.108 if a tilde (~) in the given JSON pointer s is not followed by 0 (representing ~) or 1 (representing /); see example below.

Complexity

Constant if lhs and rhs differ in the number of reference tokens, otherwise linear in the number of reference tokens.

Notes

!!! note "Operator overload resolution"

Since C++20 overload resolution will consider the _rewritten candidate_ generated from
[`operator==`](operator_eq.md).

!!! warning "Deprecation"

Overload 2 is deprecated and will be removed in a future major version release.

Examples

??? example "Example: (1) Comparing JSON pointers"

The example demonstrates comparing JSON pointers.
    
```cpp
--8<-- "examples/json_pointer__operator__notequal.cpp"
```

Output:

```
--8<-- "examples/json_pointer__operator__notequal.output"
```

??? example "Example: (2) Comparing JSON pointers and strings"

The example demonstrates comparing JSON pointers and strings, and when doing so may raise an exception.
    
```cpp
--8<-- "examples/json_pointer__operator__notequal_stringtype.cpp"
```

Output:

```
--8<-- "examples/json_pointer__operator__notequal_stringtype.output"
```

Version history

1. Added in version 2.1.0.
2. Added for backward compatibility and deprecated in version 3.11.2.