JSON for Modern C++  3.0.1

◆ at() [6/6]

template<template< typename, typename, typename... > class ObjectType = std::map, template< typename, typename... > class ArrayType = std::vector, class StringType = std::string, class BooleanType = bool, class NumberIntegerType = std::int64_t, class NumberUnsignedType = std::uint64_t, class NumberFloatType = double, template< typename > class AllocatorType = std::allocator, template< typename, typename=void > class JSONSerializer = adl_serializer>
const_reference nlohmann::basic_json::at ( const json_pointer ptr) const
inline

Returns a const reference to the element at with specified JSON pointer ptr, with bounds checking.

Parameters
[in]ptrJSON pointer to the desired element
Returns
reference to the element pointed to by ptr
Exceptions
parse_error.106if an array index in the passed JSON pointer ptr begins with '0'. See example below.
parse_error.109if an array index in the passed JSON pointer ptr is not a number. See example below.
out_of_range.401if an array index in the passed JSON pointer ptr is out of range. See example below.
out_of_range.402if the array index '-' is used in the passed JSON pointer ptr. As at provides checked access (and no elements are implicitly inserted), the index '-' is always invalid. See example below.
out_of_range.403if the JSON pointer describes a key of an object which cannot be found. See example below.
out_of_range.404if the JSON pointer ptr can not be resolved. See example below.
Exception safety Strong guarantee: if an exception is thrown, there are no
changes in the JSON value.
Complexity Constant.
Since
version 2.0.0
Example The behavior is shown in the example. at_json_pointer_const.cpp Output (play with this example at_json_pointer_const.link): at_json_pointer_const.output The example code above can be translated withg++ -std=c++11 -Isrc doc/examples/at_json_pointer_const.cpp -o at_json_pointer_const

Definition at line 13817 of file json.hpp.