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-rw-r--r--docs/wchar_and_locale.txt114
1 files changed, 114 insertions, 0 deletions
diff --git a/docs/wchar_and_locale.txt b/docs/wchar_and_locale.txt
new file mode 100644
index 000000000..67605e0bc
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+++ b/docs/wchar_and_locale.txt
@@ -0,0 +1,114 @@
+ User-configurable
+
+UCLIBC_HAS_CTYPE_TABLES
+ Make toupper etc work thru translation tables
+ and isalhum etc thru lookup tables. Help says:
+ "While the non-table versions are often smaller when building
+ statically linked apps, they work only in stub locale mode."
+
+ "stub locale mode" is when !UCLIBC_HAS_LOCALE I presume,
+ when we are permanently in POSIX/C locale.
+
+UCLIBC_HAS_CTYPE_SIGNED
+ Handle sign-extended chars. I.e. if you want
+ toupper((char)0xa0) => toupper(0xffffffa0) => still works correctly,
+ as if toupper(0xa0) was called.
+
+UCLIBC_HAS_CTYPE_UNSAFE/CHECKED/ENFORCED
+ Do not check ctype function argument's range/check it and return
+ error/check it and abort(). Help says:
+ NOTE: This only affects the 'ctype' _functions_. It does not affect
+ the macro implementations. [so what happens to macros?]
+ [examples?]
+
+UCLIBC_HAS_WCHAR
+ Wide character support. I assume all those wchar_t types and functions
+
+UCLIBC_HAS_LOCALE/XLOCALE
+ Support locale / extended locale
+
+UCLIBC_PREGENERATED_LOCALE_DATA
+ Not recommended
+
+
+ uclibc internal machinery
+
+__LOCALE_C_ONLY
+ #defined if !UCLIBC_HAS_LOCALE
+
+__NO_CTYPE
+ #defined only by some .c files. Prevents ctype macros to be #defined
+ (those w/o underscores. __ctype() macros will still be defined).
+ Looks like user is expected to never mess with defining it.
+
+__UCLIBC_DO_XLOCALE
+ #defined only by some .c files. Looks like user is expected to never
+ mess with defining it.
+
+__XL_NPP(N) - "add _l suffix if locale support is on"
+ #defined to N ## _l if __UCLIBC_HAS_XLOCALE__ && __UCLIBC_DO_XLOCALE,
+ else #defined to just N.
+
+__CTYPE_HAS_8_BIT_LOCALES
+__CTYPE_HAS_UTF_8_LOCALES
+ Depends on contents of extra/locale/LOCALES data file. Looks like
+ both will be set if UCLIBC_HAS_LOCALE and extra/locale/LOCALES
+ is not edited.
+
+__WCHAR_ENABLED
+ locale_mmap.h defines it unconditionally, extra/locale/gen_ldc.c
+ defines it too with a warning, and _then_ includes locale_mmap.h.
+ Makefile seems to prevent the warning in gen_ldc.c:
+ ifeq ($(UCLIBC_HAS_WCHAR),y)
+ BUILD_CFLAGS-gen_wc8bit += -DDO_WIDE_CHAR=1
+ BUILD_CFLAGS-gen_ldc += -D__WCHAR_ENABLED=1
+ endif
+ A mess. Why they can't just use __UCLIBC_HAS_WCHAR__?
+
+__WCHAR_REPLACEMENT_CHAR
+ Never defined (dead code???)
+
+
+
+ Actual ctype macros are a bloody mess!
+
+ctype.h
+...
+...
+#define __isctype(c, type) \
+ ((__UCLIBC_CTYPE_B)[(int) (c)] & (__ctype_mask_t) type)
+
+#define __isascii(c) (((c) & ~0x7f) == 0) /* If C is a 7 bit value. */
+#define __toascii(c) ((c) & 0x7f) /* Mask off high bits. */
+#define __isdigit_char(C) (((unsigned char)((C) - '0')) <= 9)
+#define __isdigit_int(C) (((unsigned int)((C) - '0')) <= 9)
+
+# define isalnum(c) __isctype((c), _ISalnum)
+# define isalpha(c) __isctype((c), _ISalpha)
+
+# if __GNUC__ >= 2 && defined __OPTIMIZE__ && !defined __cplusplus
+# define tolower(c) __tobody (c, tolower, __UCLIBC_CTYPE_TOLOWER, (c))
+# define toupper(c) __tobody (c, toupper, __UCLIBC_CTYPE_TOUPPER, (c))
+# endif /* Optimizing gcc */
+
+# if defined __USE_SVID || defined __USE_MISC || defined __USE_XOPEN
+# define isascii(c) __isascii (c)
+# define toascii(c) __toascii (c)
+# define _tolower(c) ((int) (__UCLIBC_CTYPE_TOLOWER)[(int) (c)])
+# define _toupper(c) ((int) (__UCLIBC_CTYPE_TOUPPER)[(int) (c)])
+# endif
+...
+...
+
+bits/uClibc_ctype.h
+...
+...
+#define __tolower(c) __body(tolower,c)
+#define __toupper(c) __body(toupper,c)
+
+#define _toupper(c) ((c) ^ 0x20)
+#define _tolower(c) ((c) | 0x20)
+...
+...
+
+WTF?! We have (at least) TWO DIFFERENT _tolower's?