Files
json/docs/mkdocs/docs/examples/basic_json_document__read.cpp
T
Niels Lohmann 061c30310e Document json_document and json_view
- API pages for basic_json_document and basic_json_view, one per member,
  and for the four aliases, each with an example
- features/json_view.md: the problem the view solves, ownership and
  lifetime, what matches basic_json::parse() and what differs, and when
  to choose json, ordered_json, SAX, or the view
- the examples show why one would use the view, not only how: borrowed
  vs. owned input, reading a few fields and materializing one subtree,
  reusing a document across many messages
- registered in the mkdocs navigation, llms.txt, the docset, the
  exceptions page (out_of_range.416), architecture.md, the integration
  page, and the README; the yyjson credit is added to the README and
  license.md

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
2026-09-30 20:58:44 +02:00

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832 B
C++

#include <iostream>
#include <string>
#include <vector>
#include <nlohmann/json_view.hpp>
using json_document = nlohmann::json_document;
int main()
{
std::cout << std::boolalpha;
std::vector<std::string> messages =
{
R"({"id": 1})", R"({"id": 2, "tag": "x"})", R"({"id": 3})"
};
// parse into the same document over and over: its node index and decode
// buffer are reused instead of being freed and reallocated for each message
json_document doc;
std::size_t total = 0;
for (const auto& msg : messages)
{
doc.read(msg);
total += doc.root().size();
}
std::cout << total << '\n';
// read() can also change what kind of input is owned/borrowed between calls
doc.read(std::string(R"({"owned": true})"));
std::cout << doc.owns_source() << '\n';
}