Summary

norlit-libc is a C library for x86 and x64.

norlit-libc is designed to conform to ISO C standard as well as those defined POSIX standard in the standard headers. norlit-libc do not intend to support other POSIX-specific headers, but may create stubs for them since they are not available in freestanding environment.

Header	Status
<assert.h>	Implemented
<complex.h>	Not supported [1]
<ctype.h>	Implemented
<errno.h>	Implemented
<fenv.h>	Under consideration
<float.h>	Implemented [9]
<inttypes.h>	Implemented
<iso646.h>	Implemented
<limits.h>	Implemented (ISO C)
<locale.h>	Implemented
<math.h>	28/69 (ISO C), 0/6 (POSIX) [4]
<setjmp.h>	Implemented (ISO C) 2/4 (POSIX) [8]
<signal.h>	Stub
<stdalign.h>	Implemented
<stdarg.h>	Implemented
<stdatomic.h>	Freestanding [2]
<stdbool.h>	Implemented
<stddef.h>	Implemented
<stdint.h>	Implemented
<stdio.h>	Implemented (ISO C) [5] 4/22 (POSIX)
<stdlib.h>	Implemented (ISO C) [3] 4/27 (POSIX) [7]
<stdnoreturn.h>	Implemented
<string.h>	Implemented
<tgmath.h>	Freestanding [2]
<threads.h>	Not supported [1]
<time.h>	Stub
<uchar.h>	Not supported [6]
<wchar.h>	Stub [6]
<wctype.h>	Not supported [6]

[1]	(1, 2) Conditional features are not in priority

[2]	(1, 2) In GCC it is available in freestanding environment, though C11 does not require it

[3]	system is a stub and will abort on call

[4]	Floating point numbers-related functions may have larger margin of error than expected

[5]	remove, rename, tmpfile and tmpnam not supported. POSIX extension to printf and scanf is not yet supported.

[6]	(1, 2, 3) Intended, but violate the standard

[7]	long double <-> string conversion is approximated with double <-> string conversion

[8]	Current there is only x86 support

[9]	FLT_ROUND and FLT_EVAL_METHOD are not implemented and will abort when used

TODO List

• Macros in errno.h and signal.h should be system dependent, extract them to include/sys in some way
• stdio.h

wchar and uchar

norlit-libc currently has no need for uchar and legacy wchar support. Related functions are defined but not implemented. Here is the list.

• <uchar.h>, <wchar.h> and <wctype.h>
• mblen, mbtowc, wctomb
• mbstowcs, wcstombs
• From <inttypes.h>: wcstoimax, wcstoumax

Thread-safety and reentrancy

norlit-libc currently has no need for multi-threading, so thread-safe is not concerned. If future support for thread-safety is needed, convert all static variables to thread-local storage or add locks to them. Reentrancy support is also not considered currently.

Locale

norlit-libc currently has no need for locale, so only C/POSIX locale is supported. When implementing norlit-libc, functions use current locale will be redirected to *_l functions by first retrieving locale by uselocale((locale_t)0). *_l will do the job instead. To support multiple locale, simply reimplement all files under src/locale