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api/json_pointer/operator_eq.md

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+# <small>nlohmann::json_pointer::</small>operator==
+
+```cpp
+// 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)
+
+// since C++20
+class json_pointer {
+    template<typename RefStringTypeRhs>
+    bool operator==(
+        const json_pointer<RefStringTypeRhs>& rhs) const noexcept;  // (1)
+
+    bool operator==(const string_t& rhs) const;                     // (2)
+};
+```
+
+1. Compares two JSON pointers for equality by comparing their reference tokens.
+
+2. Compares a JSON pointer and a string or a string and a JSON pointer for equality 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`](string_t.md))
+
+## Parameters
+
+`lhs` (in)
+:   first value to consider
+
+`rhs` (in)
+:   second value to consider
+
+## Return value
+
+whether the values `lhs`/`*this` and `rhs` are 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](../../home/exceptions.md#jsonexceptionparse_error107) if the given JSON pointer `s` is
+     nonempty and does not begin with a slash (`/`); see example below.
+   - Throws [parse_error.108](../../home/exceptions.md#jsonexceptionparse_error108) 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
+
+!!! 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__equal.cpp"
+    ```
+    
+    Output:
+    
+    ```
+    --8<-- "examples/json_pointer__operator__equal.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__equal_stringtype.cpp"
+    ```
+    
+    Output:
+    
+    ```
+    --8<-- "examples/json_pointer__operator__equal_stringtype.output"
+    ```
+
+## Version history
+
+1. Added in version 2.1.0. Added C++20 member functions in version 3.11.2.
+2. Added for backward compatibility and deprecated in version 3.11.2.