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json/docs
Niels Lohmann 606c1e710b Validate non-ASCII strings with SSSE3 on every x86-64 CPU that has it
The vector UTF-8 check of json_view needed SSSE3 at compile time
(JSON_VIEW_USE_SSSE3 with -mssse3), so default x86-64 builds validated
non-ASCII text one sequence at a time. The check is now compiled for
SSSE3 with a function attribute (GCC 4.9 and later, Clang; MSVC compiles
the intrinsics anyway) and used where CPUID reports SSSE3. The answer is
kept in an atomic that is initialized at compile time, so neither a
guard nor a global constructor is needed. The definitions do not depend
on compiler flags, so there is no ODR issue. JSON_VIEW_USE_SSSE3 now only
skips the CPU check.

On x86-64 Linux (Haswell), twitter.json parses 23% faster with Clang 18
and 25-34% faster with GCC 13, now ahead of yyjson.

Also always inline read_eight_bytes() and parse_eight_digits(): GCC
called both in the number loops of the lexer and of json_view (52 call
sites), which cost about 10% on citm_catalog.json at -O2.

Document that reusing a document with read() avoids the page faults of
a fresh node index (about 40% of a 55 MB parse on x86-64 Linux).

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
2026-10-05 20:16:24 +02:00
..
2025-04-11 10:41:14 +02:00
2025-04-11 10:41:14 +02:00

Documentation

Generate documentation

Note on documentation: The source files contain links to the online documentation at https://json.nlohmann.me.
This URL provides the most recent documentation and also applies to previous versions. Documentation for deprecated functions is not removed; instead, it is marked as deprecated.

If you want to view the documentation for a specific tag or commit hash, you can generate it locally as follows (example using tag v3.10.2):

git clone https://github.com/nlohmann/json.git
cd json
git checkout v3.10.2
make install_venv serve -C docs/mkdocs

Open http://127.0.0.1:8000/ in your browser. Replace any URL in the source code that points to https://json.nlohmann.me with http://127.0.0.1:8000 to view the documentation for the selected tag or commit hash.