Files
json/docs/mkdocs/docs/api/basic_json/number_integer_t.md
Niels Lohmann 791cd88dfc Fix raw-TeX formulas and other documentation infrastructure debt (#5736)
* Fix math formulas rendering as raw TeX in the published docs

The privacy plugin self-hosts MathJax 2.7.0 but drops its
?config=TeX-MML-AM_CHTML query string, so the rehosted script loads no
input jax and the 10 formulas across 6 pages render as raw TeX to
readers. Remove pymdownx.arithmatex and the MathJax extra_javascript
entry, and rewrite the formulas in plain HTML (<sup>, <i>) instead.
This also drops a nine-year-old third-party script from every page.

Part of #5718

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Fix publish_documentation triggers and persist unneeded git credentials

publish_documentation.yml only triggered on docs/mkdocs/** pushes, but
the site also embeds .github/CODE_OF_CONDUCT.md, CONTRIBUTING.md,
SECURITY.md, cmake/{clang,gcc}_flags.cmake, .clang-tidy,
tools/astyle/.astylerc and tests/fmt_formatter/project/main.cpp via
pymdownx.snippets, so changes to those files never republished the
site. Extend the path filter to cover them, and switch runs-on from
the long-pinned ubuntu-22.04 to ubuntu-latest to match
ci_test_documentation.

Also add persist-credentials: false to the checkouts in ci_icpx and
ci_nvhpc (ubuntu.yml) and msvc-vs2026/msvc-arm64 (windows.yml), none
of which pushes with git, matching every other checkout in these
workflows.

Part of #5718

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Fix example build: broken debug echo, deprecations hidden for everything

docs/Makefile's debug echo used a space instead of a comma in
$(call cxx_standard ...), so it always printed an empty standard.
Every example was also compiled with -Wno-deprecated-declarations,
which would silently hide an accidental deprecated-API call in any of
them. Factor the duplicated compile flags into EXAMPLE_CPPFLAGS/
EXAMPLE_WARNFLAGS, build with -Werror=deprecated-declarations by
default, and only allow the three examples that intentionally
document deprecated API (the DEPRECATED_EXAMPLES list) to suppress it.

Part of #5718

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Fix check_structure.py NOLINT parsing and an off-by-one report line

`line.strip("<!-- NOLINT")` followed by `.strip(" -->")` strips any of
the characters in those sets from both ends, not a literal prefix; it
only happened to work for "Examples". A NOLINT'd section name
starting with N, O, L, I or T (e.g. "Notes", "Template parameters",
"Iterator invalidation", "Literals") was silently mangled, so the
suppression did not apply and the checker could report a spurious
missing/misordered section. Parse the comment with a regex instead.
The same fragile strip() pattern was used for heading text; replace it
with a plain prefix slice. Also fix the admonition_title report, which
used the 0-based line index while every other report in the file uses
lineno+1.

Part of #5718

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Fix docset README's non-existent make target and stale fallback URL

The README told readers to run `make nlohmann_json.docset`, but the
Makefile's targets are `all`, `JSON_for_Modern_C++.docset` and
`install_docset_zeal`; the documented command has failed with "No
rule to make target" since #2967 (2021). Point the README at the real
target and folder name. Info.plist's DashDocSetFallbackURL also still
pointed at the old nlohmann.github.io/json/ URL instead of the
canonical https://json.nlohmann.me/ from mkdocs.yml's site_url.

Leave list_missing_pages/list_removed_paths alone: they may become
redundant once #5638's check_docset() lands, which is a follow-up.

Part of #5718

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Remove two leftover Doxygen-era .link files from the examples directory

parse__iterator_pair.link and parse__pointers.link each held only a
Wandbox "online" permalink from the old Doxygen docs. #3071 deleted
every other .link file in 2021; these two came in through a parallel
PR (#3100) and were never referenced by any page, script or config.

Part of #5718

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Fix MacPorts CMake example to include its own snippet files

The MacPorts "Example: CMake" block included
integration/homebrew/example.cpp and
integration/homebrew/CMakeLists.txt instead of the MacPorts files
right next to it, a copy-paste slip from the Homebrew section. Nothing
referenced integration/macports/CMakeLists.txt as a result. The page
rendered correctly only because the homebrew, macports and
vcpkg/CMakeLists.txt snippets are byte-identical, so a future edit to
the MacPorts files would not have shown up on the page.

Part of #5718 item 6

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Do not persist git credentials in publish_documentation's checkout

The checkout step in publish_documentation.yml left the default
persist-credentials: true, so GITHUB_TOKEN stayed writable in
.git/config for the rest of the job (zizmor's artipacked finding). The
Deploy documentation step authenticates through its own github_token
input to peaceiris/actions-gh-pages and does not push with the
checked-out credentials, so persist-credentials: false is safe here,
matching every other checkout in the workflow set.

Overlaps #5638, which edits this same checkout step (adds
fetch-depth: 0); expect a rebase conflict there.

Part of #5718 item 2

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Replace list_missing_pages/list_removed_paths with a comm(1)-based diff

The docset Makefile's list_missing_pages ran one sqlite3 query per
mkdocs page, and list_removed_paths nested a loop over all mkdocs pages
inside a loop over all docset index paths (O(n*m) shell iteration).
Issue #5718 item 5 suggested removing or reducing these targets once
#5638's check_docset() lands, but that PR is still open and covers only
API pages and macros, not the full page set these targets check.
Replace the loops with two sorted path lists (DOCSET_PAGE_PATHS from
mkdocs' markdown sources, DOCSET_INDEX_PATHS from the built docset
index) compared with a single comm(1) call each, verified to produce
output identical to the old loops against the current docSet.dsidx.

The sed expression used '#' as its delimiter, which GNU Make reads as
a comment character even inside a variable assignment, truncating the
line and orphaning the closing paren of $(shell ...) ("unterminated
call to function 'shell': missing ')'"). Use '@' as the delimiter
instead.

Part of #5718 item 5

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

---------

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
2026-09-30 22:15:20 +02:00

3.5 KiB

nlohmann::basic_json::number_integer_t

using number_integer_t = NumberIntegerType;

The type used to store JSON numbers (integers).

RFC 8259 describes numbers as follows:

The representation of numbers is similar to that used in most programming languages. A number is represented in base 10 using decimal digits. It contains an integer component that may be prefixed with an optional minus sign, which may be followed by a fraction part and/or an exponent part. Leading zeros are not allowed. (...) Numeric values that cannot be represented in the grammar below (such as Infinity and NaN) are not permitted.

This description includes both integer and floating-point numbers. However, C++ allows more precise storage if it is known whether the number is a signed integer, an unsigned integer, or a floating-point number. Therefore, three different types, number_integer_t, number_unsigned_t and number_float_t are used.

To store integer numbers in C++, a type is defined by the template parameter NumberIntegerType which chooses the type to use.

Template parameters

NumberIntegerType
the type to store signed integers. It must be a signed integral type (#!cpp std::is_integral) with a #!cpp std::numeric_limits specialization, and it is stored directly inside a basic_json value. See Template Parameter Requirements.

Notes

Default type

With the default values for NumberIntegerType (std::int64_t), the default value for number_integer_t is #!cpp std::int64_t.

Default behavior

  • The restrictions about leading zeros are not enforced in C++. Instead, leading zeros in integer literals lead to an interpretation as an octal number. Internally, the value will be stored as a decimal number. For instance, the C++ integer literal 010 will be serialized to 8. During deserialization, leading zeros yield an error.

Limits

RFC 8259 specifies:

An implementation may set limits on the range and precision of numbers.

When the default type is used, the maximal integer number that can be stored is 9223372036854775807 (INT64_MAX) and the minimal integer number that can be stored is -9223372036854775808 (INT64_MIN). Integer numbers that are out of range will yield over/underflow when used in a constructor. During deserialization, too large or small integer numbers will automatically be stored as number_unsigned_t or number_float_t.

RFC 8259 further states:

Note that when such software is used, numbers that are integers and are in the range [-253+1, 253-1] are interoperable in the sense that implementations will agree exactly on their numeric values.

As this range is a subrange of the exactly supported range [INT64_MIN, INT64_MAX], this class's integer type is interoperable.

Storage

Integer number values are stored directly inside a basic_json type.

Examples

??? example

The following code shows that `number_integer_t` is by default, a typedef to `#!cpp std::int64_t`.
 
```cpp
--8<-- "examples/number_integer_t.cpp"
```

Output:

```json
--8<-- "examples/number_integer_t.output"
```

Version history

  • Added in version 1.0.0.