This file describes the implementation status and some notes; information is
taken from the C99 standard (ISO/IEC 9899:1999), section 7 ("Library").

# Notes for implementers

7.1.2§6:
  Use (extern) in all function prototypes
7.1.3§1:
  Only expose standard identifiers; anything else might be defined as a macro.
  Make sure every argument name, internal function name, etc. starts with
  either "__" or "_X" (where X is any uppercase letter)
7.1.4§1:
  Always give a function even if there is a macro definition, so that the
  address of the function can be taken; don't rely on the macro being defined,
  as the user can remove it except in some special cases

String functions (mainly in <string.h>) can use 4-byte accesses, and in doing
so read up to 3 bytes after the end of the string if it is not padded (which
malloc'd strings and literal strings both are, leaving only stack-allocated and
statically-allocated ones). This allows important speed optimizations. The
extra access cannot trigger memory protection because there is no valid memory
less than 4 bytes before the end of any protection region. The extra access
might trigger the UBC in very specific scenarios, but we don't really care.

# Status

In this file, every definition is classified in one of several implementation
statuses. There are 5 stages that every definition should go through.

TODO:       Function/symbol/macro is not implemented/defined
BDEPS(...): Function/symbol/macro needs ... to build
LDEPS(...): Function/symbol/macro needs ... to link
TEST:       Function/symbol/macro needs to be tested
DONE:       Function/symbol/macro is defined, builds, links, and is tested

7.2 <assert.h>
!   7.2.1 assert: LDEPS(fprintf,stderr)

7.3 <complex.h> => OpenLibm

7.4 <ctype.h>
    7.4.1 is*: DONE
    7.4.2 to*: DONE

7.5 <errno.h>
    7.5.2 EDOM EILSEQ ERANGE: DONE

7.6 <fenv.h> => OpenLibm

7.7 <float.h> => GCC

7.8 <inttypes.h>
!   7.8.1   PRI* macros: LDEPS(*printf)
!   7.8.1   SCN* macros: LDEPS(*scanf)
    7.8.2.1 imaxabs: DONE
    7.8.2.2 imaxdiv: DONE
    7.8.2.3 strtoimax strtoumax: DONE
!   7.8.2.4 wcstoimax wcstoumax: TODO

7.9 <iso646.h> => GCC

7.10 <limits.h> => GCC

7.11 <locale.h>
!    7.11.1 setlocale: TEST
!    7.11.2 localeconv: TEST

7.12 <math.h> => OpenLibm

7.13 <setjmp.h>
     7.13.1 setjmp: DONE
     7.13.2 longjmp: DONE

7.14 <signal.h>
     7.14      sig_atomic_t SIG_DFL SIG_ERR SIG_IGN: DONE
     7.14      SIGABRT SIGFPE SIGILL SIGINT SIGSEGV SIGTERM: DONE
     7.14.1.1  signal: DONE
     7.14.1.2  raise: DONE

7.15 <stdarg.h> => GCC

7.16 <stdbool.h> => GCC

7.17 <stddef.h> => GCC

7.18 <stdint.h> => GCC

7.19 <stdio.h>
     7.19.1  Introduction: TEST
             TODO: Handle wide-oriented streams? (see notes)
!    7.19.4  Operations on files: TODO
!    7.19.5  File access functions: TODO
!    7.19.6  Formatted input/output functions: TODO
!    7.19.7  Character input/output functions: TODO
!    7.19.8  Direct input/output functions: TODO
!    7.19.9  File positioning functions: TODO
!    7.19.10 Error-handling functions: TODO

7.20 <stdlib.h>
     7.20      RAND_MAX: DONE
!    7.20      MB_CUR_MAX: TODO
     7.20.1.1  atof: DONE
     7.20.1.2  atoi, atol, atoll: DONE
     7.20.1.3  strtod, strtof, strtold: DONE
     7.20.1.4  strtol, strtoul, strtoll, strtoull: DONE
     7.20.2.1  rand: DONE
     7.20.2.2  srand: DONE
     7.20.3.1  calloc: DONE
     7.20.3.2  free: DONE       (at least gint)
     7.20.3.3  malloc: DONE     (at least gint)
     7.20.3.4  realloc: DONE    (at least gint)
     7.20.4.1  abort: DONE
!    7.20.4.2  atexit: TODO
     7.20.4.3  exit: DONE       (missing stream flushing/closing/etc)
     7.20.4.4  _Exit: DONE      (gint only)
!    7.20.4.5  getenv: TODO
!    7.20.4.6  system: TODO
!    7.20.5.1  bsearch: TODO
!    7.20.5.2  qsort: TEST
     7.20.6.1  abs, labs, llabs: DONE
     7.20.6.2  div, ldiv, lldiv: DONE
!    7.20.7  Multibyte/wide character conversion functions: TODO
!    7.20.8  Multibyte/wide string conversion functions: TODO

7.21 <string.h>
     7.21.2.1  memcpy: DONE
     7.21.2.2  memmove: DONE    (Unoptimized: byte-by-byte)
     7.21.2.3  strcpy: DONE
     7.21.2.4  strncpy: DONE
     7.21.3.1  strcat: DONE
     7.21.3.2  strncat: DONE
     7.21.4.1  memcmp: DONE
     7.21.4.2  strcmp: DONE
     7.21.4.3  strcoll: DONE
     7.21.4.4  strncmp: DONE
     7.21.4.5  strxfrm: DONE
     7.21.5.1  memchr: DONE
     7.21.5.2  strchr: DONE
     7.21.5.3  strcspn: DONE
     7.21.5.4  strpbrk: DONE
     7.21.5.5  strrchr: DONE
     7.21.5.6  strspn: DONE
     7.21.5.7  strstr: DONE
     7.21.5.8  strtok: DONE
     7.21.6.1  memset: DONE
     7.21.6.2  strerror: DONE
     7.21.6.3  strlen: DONE
     Extensions:
     - strnlen: DONE
     - strchrnul: DONE
     - strcasestr: DONE
     - strcasecmp: DONE
     - strncasecmp: DONE
     - strdup: DONE
     - strndup: DONE

7.22 <tgmath.h> => GCC

7.23 <time.h>
!    7.23.1    Components of time: TODO
!    7.23.2.1  clock: TODO
!    7.23.2.2  difftime: TODO
!    7.23.2.3  mktime: TODO
!    7.23.2.4  time: TODO
!    7.23.3.1  asctime: TODO
!    7.23.3.2  ctime: TODO
!    7.23.3.3  gmtime: TODO
!    7.23.3.4  localtime: TODO
!    7.23.3.5  strftime: TODO

7.24 <wchar.h>
     TODO (not a priority)

7.25 <wctype.h>
     TODO (not a priority)

# Supporting locales

What if we wanted to support more locales?
-> Need to a mechanism to supply the raw information, similar to the text files
   in /usr/share/i18n/locales
-> Implement setlocale() and localeconv() properly (not hard)
-> Probably support nl_langinfo(), which is much better than localeconv()
-> Fix the "TODO: locale: ..." messages wherever assumptions on the locale are
   made in the code
-> Properly implement strcoll() and strxfrm()

# Supporting text and binary files (newline translation)

Because of 7.19.2%1,223 we don't need to support newline translation.

# Support wide-oriented streams

This requires all the wide-char functions but also updating fpos_t to be a
structure with at least some mbstate_t member (7.19.2§6).

I really don't want to do that. Use multi-byte functions with UTF-8.