Embedded Libraries for Developers

What is it?

This roadmap is the developer-facing view of the third-party code compiled into Impossible OS: the freestanding string and maths library, miniz, Monocypher and the kernel random generator, cJSON, a Mbed TLS subset and the STB image and font headers. Most of what it lists has already shipped under the kernel libraries roadmap, Kernel Embedded Libraries, with different file names from the ones this file uses. What is still missing is a ZIP writer, a TLS client, one home for the STB headers and a host-side library test script.

How does it work?

Today. The libraries are compiled into the kernel image:

Strings and formatting. snprintf(), vsnprintf(), memchr(), strrchr() and the rest live in string.h and string.c, under src/libc/, not the src/libs/libc/ this roadmap names.
Maths. kmath_sin(), kmath_tan(), kmath_atan2(), kmath_asin(), kmath_exp(), kmath_log(), kmath_log2(), kmath_log10(), kmath_round(), kmath_trunc() and kmath_cbrt() are in math.h. The older double helpers in include/kernel/kmath.h stay for the font rasterizer.
Random numbers. csprng_fill() in csprng.h fills a buffer from the kernel generator in csprng.c, which is built on the vendored Monocypher. User mode reaches it through the native call NtGetRandom (service 0x03D8), not a SYS_GETRANDOM number.
JSON. cJSON is vendored in src/libs/cjson/; kernel code uses the small wrapper in json.h (json_int(), json_bool(), json_free() and friends).
Images. stb_image.h, stb_image_write.h and stb_truetype.h sit in include/ and are instantiated once each in the image, image-save and font code; image_save_png() and image_save_bmp() write files.
Vendored but not built. miniz and Mbed TLS are in src/libs/, but the Makefile excludes both directories from the kernel build, so neither is linked today.

Planned design. Keep each library in one place, then add what developers still lack: a ZIP writer and streaming deflate on top of miniz, a TLS 1.2 client built from the Mbed TLS subset with a CA bundle, a single src/libs/stb/ home, and scripts/test-libs.sh so the libraries can be tested on the host.

flowchart LR
    A[Kernel libraries roadmap] -->|shipped| B[string, maths, CSPRNG, cJSON]
    C[This roadmap] -->|planned| D[ZIP writer, TLS client, host tests]
    B --> D

What are its interfaces?

Interface	Status
`snprintf()`, `vsnprintf()`, `memchr()`, `strrchr()`	Shipped in `src/libc/`
`kmath_*` float maths in `include/libc/math.h`	Shipped
`csprng_fill()`, `NtGetRandom`	Shipped
cJSON and the `json_*` wrapper	Shipped
`image_save_png()`, `image_save_bmp()`	Shipped
`zip_create()` and the other ZIP writer calls	Planned in section 3
`tls_connect()`, CA bundle	Planned in section 6
`scripts/test-libs.sh`	Planned in section 8

How do I use it?

Kernel code includes the header and calls the function; there is nothing to link separately. The library tests run inside the kernel test runner:

bash scripts/test.sh SUITE=exec

The klibs: suites registered in test_klibs.c cover string edge cases, LZ4 round trips and the JSON wrapper, among others.

Who owns what?

The kernel libraries roadmap, 02-kernel-core/TODO-03, owns this ground. It shipped strings (its section 1), maths (2), Monocypher and the CSPRNG (5) and cJSON (6). miniz (4) and Mbed TLS (7) are vendored there with their ports deferred: miniz still needs a caller-owned workspace allocator before it can be compiled, and its first consumer is HTTP gzip decoding. This file's ZIP writer and TLS client depend on those ports. This file restates the owner's sections with other paths. That overlap is filed as a rescope item in this roadmap's section 1, which keeps only the deltas.

What is not implemented yet?

String Library Consolidation: strcasestr(), itoa() and strtoull() do not exist yet
Math Library Extension: most functions shipped in math.h; kmath_remainder() and the KMATH_PI, KMATH_E, KMATH_SQRT2 and KMATH_LN2 constants are still missing
miniz ZIP Writer and Stream Extension
monocypher, CSPRNG and SYS_GETRANDOM: shipped as NtGetRandom under the kernel libraries roadmap
cJSON: shipped; the roadmap's lowercase file names and cJSON_InitHooks() set-up do not match the tree
Mbed TLS Subset
STB Consolidation and stb_image_write
Library Integration Tests and README

How does it compare with Windows 11 and Linux?

Windows builds its kernel against the MSVC runtime and ships deflate through LZNT1 and Cabinet.dll, random numbers through BCryptGenRandom and TLS through Schannel. Linux keeps its own lib/string.c, an in-tree zlib and get_random_bytes(), and leaves TLS to user space. Impossible OS takes the permissive upstreams directly (miniz, Monocypher, cJSON, Mbed TLS, STB) and exposes randomness through one native call. Unlike either, it has a JSON parser in the kernel for configuration and health reports.