{
"errno": {
"LIBC_CONF_ERRNO_MODE": {
"value": "LIBC_ERRNO_MODE_DEFAULT",
"doc": "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, and LIBC_ERRNO_MODE_SYSTEM_INLINE."
}
},
"threads": {
"LIBC_CONF_THREAD_MODE": {
"value": "LIBC_THREAD_MODE_PLATFORM",
"doc": "The implementation used for Mutex, acceptable values are LIBC_THREAD_MODE_PLATFORM, LIBC_THREAD_MODE_SINGLE, and LIBC_THREAD_MODE_EXTERNAL."
}
},
"printf": {
"LIBC_CONF_PRINTF_DISABLE_FLOAT": {
"value": false,
"doc": "Disable printing floating point values in printf and friends."
},
"LIBC_CONF_PRINTF_DISABLE_INDEX_MODE": {
"value": false,
"doc": "Disable index mode in the printf format string."
},
"LIBC_CONF_PRINTF_DISABLE_WRITE_INT": {
"value": false,
"doc": "Disable handling of %n in printf format string."
},
"LIBC_CONF_PRINTF_FLOAT_TO_STR_USE_MEGA_LONG_DOUBLE_TABLE": {
"value": false,
"doc": "Use large table for better printf long double performance."
},
"LIBC_CONF_PRINTF_FLOAT_TO_STR_USE_DYADIC_FLOAT": {
"value": false,
"doc": "Use dyadic float for faster and smaller but less accurate printf doubles."
},
"LIBC_CONF_PRINTF_FLOAT_TO_STR_NO_SPECIALIZE_LD": {
"value": false,
"doc": "Use the same mode for double and long double in printf."
},
"LIBC_CONF_PRINTF_FLOAT_TO_STR_USE_FLOAT320": {
"value": false,
"doc": "Use an alternative printf float implementation based on 320-bit floats"
},
"LIBC_CONF_PRINTF_DISABLE_FIXED_POINT": {
"value": false,
"doc": "Disable printing fixed point values in printf and friends."
},
"LIBC_CONF_PRINTF_DISABLE_STRERROR": {
"value": false,
"doc": "Disable handling of %m to print strerror in printf and friends."
},
"LIBC_CONF_PRINTF_RUNTIME_DISPATCH": {
"value": true,
"doc": "Use dynamic dispatch for the output mechanism to reduce code size."
},
"LIBC_CONF_PRINTF_DISABLE_WIDE": {
"value": false,
"doc": "Disable handling wide characters for printf and friends."
},
"LIBC_COPT_PRINTF_DISABLE_BITINT": {
"value": false,
"doc": "Disable bitint length modifiers to reduce code size. Specifically the wNUM and wfNUM modifiers."
}
},
"scanf": {
"LIBC_CONF_SCANF_DISABLE_FLOAT": {
"value": false,
"doc": "Disable parsing floating point values in scanf and friends."
},
"LIBC_CONF_SCANF_DISABLE_INDEX_MODE": {
"value": false,
"doc": "Disable index mode in the scanf format string."
}
},
"str_to_float": {
"LIBC_CONF_STRTOFLOAT_DISABLE_EISEL_LEMIRE": {
"value": false,
"doc": "Disable Eisel-Lemire algorithm for string to float conversion."
},
"LIBC_CONF_STRTOFLOAT_DISABLE_SIMPLE_DECIMAL_CONVERSION": {
"value": false,
"doc": "Disable simple decimal conversion for string to float conversion."
},
"LIBC_CONF_STRTOFLOAT_DISABLE_CLINGER_FAST_PATH": {
"value": false,
"doc": "Disable Clinger's fast path for string to float conversion."
}
},
"string": {
"LIBC_CONF_STRING_LENGTH_IMPL": {
"value": "element",
"doc": "Selects the implementation for string-length: 'element', 'word', 'clang_vector', or 'arch_vector'."
},
"LIBC_CONF_FIND_FIRST_CHARACTER_IMPL": {
"value": "element",
"doc": "Selects the implementation for find-first-character-related functions: 'element', 'word', 'clang_vector', or 'arch_vector'."
},
"LIBC_CONF_MEMSET_X86_USE_SOFTWARE_PREFETCHING": {
"value": false,
"doc": "Inserts prefetch for write instructions (PREFETCHW) for memset on x86 to recover performance when hardware prefetcher is disabled."
}
},
"codegen": {
"LIBC_CONF_KEEP_FRAME_POINTER": {
"value": true,
"doc": "Keep frame pointer in functions for better debugging experience."
},
"LIBC_CONF_ENABLE_STRONG_STACK_PROTECTOR": {
"value": true,
"doc": "Enable -fstack-protector-strong to defend against stack smashing attack."
}
},
"pthread": {
"LIBC_CONF_TIMEOUT_ENSURE_MONOTONICITY": {
"value": true,
"doc": "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."
},
"LIBC_CONF_RAW_MUTEX_DEFAULT_SPIN_COUNT": {
"value": 100,
"doc": "Default number of spins before blocking if a mutex is in contention (default to 100)."
},
"LIBC_CONF_RWLOCK_DEFAULT_SPIN_COUNT": {
"value": 100,
"doc": "Default number of spins before blocking if a rwlock is in contention (default to 100)."
}
},
"math": {
"LIBC_CONF_MATH_OPTIMIZATIONS": {
"value": 0,
"doc": "Configure optimizations for math functions. Values accepted are LIBC_MATH_SKIP_ACCURATE_PASS, LIBC_MATH_SMALL_TABLES, LIBC_MATH_NO_ERRNO, LIBC_MATH_NO_EXCEPT, LIBC_MATH_FAST, and LIBC_MATH_INTERMEDIATE_COMP_IN_FLOAT."
},
"LIBC_CONF_FREXP_INF_NAN_EXPONENT": {
"value": "",
"doc": "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_USE_SYSTEM_FENV": {
"value": false,
"doc": "Use C standard fenv.h calls from the system libc instead our internal fenv implementations."
}
},
"qsort": {
"LIBC_CONF_QSORT_IMPL": {
"value": "LIBC_QSORT_QUICK_SORT",
"doc": "Configures sorting algorithm for qsort and qsort_r. Values accepted are LIBC_QSORT_QUICK_SORT, LIBC_QSORT_HEAP_SORT."
}
},
"setjmp": {
"LIBC_CONF_SETJMP_AARCH64_RESTORE_PLATFORM_REGISTER": {
"value": true,
"doc": "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."
}
},
"time": {
"LIBC_CONF_TIME_64BIT": {
"value": false,
"doc": "Force the size of time_t to 64 bits, even on platforms where compatibility considerations would otherwise make it 32-bit."
}
},
"general": {
"LIBC_ADD_NULL_CHECKS": {
"value": true,
"doc": "Add nullptr checks in the library's implementations to some functions for which passing nullptr is undefined behavior."
}
},
"wctype": {
"LIBC_CONF_WCTYPE_MODE": {
"value": "LIBC_WCTYPE_MODE_ASCII",
"doc": "The implementation used for wctype, acceptable values are LIBC_WCTYPE_MODE_ASCII and LIBC_WCTYPE_MODE_UTF8."
}
},
"fenv": {
"LIBC_CONF_TRAP_ON_RAISE_FP_EXCEPT": {
"value": false,
"doc": "Trap with SIGFPE when feraiseexcept is called with unmasked floating point exceptions, similar to glibc's behavior. This is currently working only on x86 with SSE."
}
}
}