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using array_t = ArrayType<basic_json, AllocatorType<basic_json>>;

The type used to store JSON arrays.

RFC 7159 describes JSON arrays as follows:

An array is an ordered sequence of zero or more values.

To store objects in C++, a type is defined by the template parameters explained below.

Template parameters

container type to store arrays (e.g., std::vector or std::list)
the allocator to use for objects (e.g., std::allocator)


Default type

With the default values for ArrayType (std::vector) and AllocatorType (std::allocator), the default value for array_t is:

  basic_json, // value_type
  std::allocator<basic_json> // allocator_type


RFC 7159 specifies:

An implementation may set limits on the maximum depth of nesting.

In this class, the array's limit of nesting is not explicitly constrained. However, a maximum depth of nesting may be introduced by the compiler or runtime environment. A theoretical limit can be queried by calling the max_size function of a JSON array.


Arrays are stored as pointers in a basic_json type. That is, for any access to array values, a pointer of type array_t* must be dereferenced.

Version history

  • Added in version 1.0.0.