Files
RedBear-OS/local/recipes/dev/libclc/source/libc/docs/configure.rst
T
vasilito cb424d7448 build: static patch-sanity linter (shift-left the malformed-patch class)
verify-patch-sanity.py validates every active recipe .patch has internally-
consistent hunk line counts — catching the 'malformed patch at line N' failure
at commit/CI/preflight time instead of hours into a cook. This cycle hit that
class three times (qtwaylandscanner, sddm, xwayland), each only discovered when
cookbook tried to apply the patch.

Running it across the repo found 29 latent malformed patches (validated against
GNU patch: e.g. relibc/P3-sysv-ipc reproduces 'malformed patch at line 22').
They were harmless only because they sit in vendored recipes (baked, not re-
applied) — but would fail on any version-bump re-derivation. --fix recounts the
hunk headers (body untouched) and repaired all 29.

Wired into build-preflight.sh (Phase 1.0D) and redbear-ci.yml, with a unit test
(test-patch-sanity.sh). Skips archived/legacy trees and unvalidatable formats
(empty placeholders, bare-@@ git hunks).
2026-08-01 05:13:02 +03:00

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ReStructuredText

.. _configure:
..
Do not edit this file directly. CMake will auto generate it.
If the changes are intended, add this file to your commit.
==========================
Configure Options
==========================
Below is the full set of options one can use to configure the libc build.
An option can be given an explicit value on the CMake command line using
the following syntax:
.. code-block:: sh
$> cmake <other build options> -D<libc config option name>=<option value> <more options>
For example:
.. code-block:: sh
$> cmake <other build options> -DLIBC_CONF_PRINTF_DISABLE_FLOAT=ON <more options>
See the main ``config/config.json``, and the platform and architecture specific
overrides in ``config/<platform>/config.json`` and ``config/<platform>/<arch>/config.json,``
to learn about the defaults for your platform and target.
* **"codegen" options**
- ``LIBC_CONF_ENABLE_STRONG_STACK_PROTECTOR``: Enable -fstack-protector-strong to defend against stack smashing attack.
- ``LIBC_CONF_KEEP_FRAME_POINTER``: Keep frame pointer in functions for better debugging experience.
* **"errno" options**
- ``LIBC_CONF_ERRNO_MODE``: The implementation used for errno, acceptable values are LIBC_ERRNO_MODE_DEFAULT, LIBC_ERRNO_MODE_UNDEFINED, LIBC_ERRNO_MODE_THREAD_LOCAL, LIBC_ERRNO_MODE_SHARED, LIBC_ERRNO_MODE_EXTERNAL, LIBC_ERRNO_MODE_SYSTEM, and LIBC_ERRNO_MODE_SYSTEM_INLINE.
* **"general" options**
- ``LIBC_ADD_NULL_CHECKS``: Add nullptr checks in the library's implementations to some functions for which passing nullptr is undefined behavior.
* **"math" options**
- ``LIBC_CONF_FREXP_INF_NAN_EXPONENT``: The value written back to the second parameter when calling frexp/frexpf/frexpl` with `+/-Inf`/`NaN` is unspecified. Configure an explicit exp value for Inf/NaN inputs.
- ``LIBC_CONF_MATH_OPTIMIZATIONS``: Configures optimizations for math functions. Values accepted are LIBC_MATH_SKIP_ACCURATE_PASS, LIBC_MATH_SMALL_TABLES, LIBC_MATH_NO_ERRNO, LIBC_MATH_NO_EXCEPT, and LIBC_MATH_FAST.
* **"printf" options**
- ``LIBC_CONF_PRINTF_DISABLE_FIXED_POINT``: Disable printing fixed point values in printf and friends.
- ``LIBC_CONF_PRINTF_DISABLE_FLOAT``: Disable printing floating point values in printf and friends.
- ``LIBC_CONF_PRINTF_DISABLE_INDEX_MODE``: Disable index mode in the printf format string.
- ``LIBC_CONF_PRINTF_DISABLE_STRERROR``: Disable handling of %m to print strerror in printf and friends.
- ``LIBC_CONF_PRINTF_DISABLE_WRITE_INT``: Disable handling of %n in printf format string.
- ``LIBC_CONF_PRINTF_FLOAT_TO_STR_NO_SPECIALIZE_LD``: Use the same mode for double and long double in printf.
- ``LIBC_CONF_PRINTF_FLOAT_TO_STR_USE_DYADIC_FLOAT``: Use dyadic float for faster and smaller but less accurate printf doubles.
- ``LIBC_CONF_PRINTF_FLOAT_TO_STR_USE_FLOAT320``: Use an alternative printf float implementation based on 320-bit floats
- ``LIBC_CONF_PRINTF_FLOAT_TO_STR_USE_MEGA_LONG_DOUBLE_TABLE``: Use large table for better printf long double performance.
- ``LIBC_CONF_PRINTF_RUNTIME_DISPATCH``: Use dynamic dispatch for the output mechanism to reduce code size.
* **"pthread" options**
- ``LIBC_CONF_RAW_MUTEX_DEFAULT_SPIN_COUNT``: Default number of spins before blocking if a mutex is in contention (default to 100).
- ``LIBC_CONF_RWLOCK_DEFAULT_SPIN_COUNT``: Default number of spins before blocking if a rwlock is in contention (default to 100).
- ``LIBC_CONF_TIMEOUT_ENSURE_MONOTONICITY``: Automatically adjust timeout to CLOCK_MONOTONIC (default to true). POSIX API may require CLOCK_REALTIME, which can be unstable and leading to unexpected behavior. This option will convert the real-time timestamp to monotonic timestamp relative to the time of call.
* **"qsort" options**
- ``LIBC_CONF_QSORT_IMPL``: Configures sorting algorithm for qsort and qsort_r. Values accepted are LIBC_QSORT_QUICK_SORT, LIBC_QSORT_HEAP_SORT.
* **"scanf" options**
- ``LIBC_CONF_SCANF_DISABLE_FLOAT``: Disable parsing floating point values in scanf and friends.
- ``LIBC_CONF_SCANF_DISABLE_INDEX_MODE``: Disable index mode in the scanf format string.
* **"setjmp" options**
- ``LIBC_CONF_SETJMP_AARCH64_RESTORE_PLATFORM_REGISTER``: Make setjmp save the value of x18, and longjmp restore it. The AArch64 ABI delegates this register to platform ABIs, which can choose whether to make it caller-saved.
* **"string" options**
- ``LIBC_CONF_MEMSET_X86_USE_SOFTWARE_PREFETCHING``: Inserts prefetch for write instructions (PREFETCHW) for memset on x86 to recover performance when hardware prefetcher is disabled.
- ``LIBC_CONF_STRING_UNSAFE_WIDE_READ``: Read more than a byte at a time to perform byte-string operations like strlen.
* **"time" options**
- ``LIBC_CONF_TIME_64BIT``: Force the size of time_t to 64 bits, even on platforms where compatibility considerations would otherwise make it 32-bit.