| 1 | /* |
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| 2 | FUNCTION |
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| 3 | <<tolower>>, <<tolower_l>>---translate characters to lowercase |
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| 4 | |
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| 5 | INDEX |
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| 6 | tolower |
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| 7 | |
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| 8 | INDEX |
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| 9 | tolower_l |
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| 10 | |
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| 11 | INDEX |
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| 12 | _tolower |
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| 13 | |
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| 14 | SYNOPSIS |
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| 15 | #include <ctype.h> |
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| 16 | int tolower(int <[c]>); |
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| 17 | int _tolower(int <[c]>); |
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| 18 | |
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| 19 | #include <ctype.h> |
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| 20 | int tolower_l(int <[c]>, locale_t <[locale]>); |
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| 21 | |
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| 22 | |
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| 23 | DESCRIPTION |
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| 24 | <<tolower>> is a macro which converts uppercase characters to lowercase, |
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| 25 | leaving all other characters unchanged. It is only defined when |
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| 26 | <[c]> is an integer in the range <<EOF>> to <<255>>. |
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| 27 | |
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| 28 | <<tolower_l>> is like <<tolower>> but performs the function based on the |
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| 29 | locale specified by the locale object locale. If <[locale]> is |
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| 30 | LC_GLOBAL_LOCALE or not a valid locale object, the behaviour is undefined. |
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| 31 | |
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| 32 | You can use a compiled subroutine instead of the macro definition by |
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| 33 | undefining this macro using `<<#undef tolower>>' or `<<#undef tolower_l>>'. |
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| 34 | |
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| 35 | <<_tolower>> performs the same conversion as <<tolower>>, but should |
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| 36 | only be used when <[c]> is known to be an uppercase character (<<A>>--<<Z>>). |
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| 37 | |
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| 38 | RETURNS |
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| 39 | <<tolower>>, <<tolower_l>> return the lowercase equivalent of <[c]> when |
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| 40 | <[c]> is an uppercase character, and <[c]> otherwise. |
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| 41 | |
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| 42 | <<_tolower>> returns the lowercase equivalent of <[c]> when it is a |
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| 43 | character between <<A>> and <<Z>>. If <[c]> is not one of these |
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| 44 | characters, the behaviour of <<_tolower>> is undefined. |
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| 45 | |
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| 46 | PORTABILITY |
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| 47 | <<tolower>> is ANSI C. <<_tolower>> is not recommended for portable programs. |
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| 48 | <<tolower_l>> is POSIX-1.2008. |
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| 49 | |
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| 50 | No supporting OS subroutines are required. |
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| 51 | */ |
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| 52 | |
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| 53 | #include <_ansi.h> |
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| 54 | #include <ctype.h> |
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| 55 | #if defined (_MB_EXTENDED_CHARSETS_ISO) || defined (_MB_EXTENDED_CHARSETS_WINDOWS) |
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| 56 | #include <limits.h> |
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| 57 | #include <stdio.h> |
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| 58 | #include <stdlib.h> |
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| 59 | #include <wctype.h> |
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| 60 | #include <wchar.h> |
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| 61 | #endif |
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| 62 | |
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| 63 | #undef tolower |
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| 64 | int |
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| 65 | tolower (int c) |
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| 66 | { |
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| 67 | #if defined (_MB_EXTENDED_CHARSETS_ISO) || defined (_MB_EXTENDED_CHARSETS_WINDOWS) |
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| 68 | if ((unsigned char) c <= 0x7f) |
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| 69 | return isupper (c) ? c - 'A' + 'a' : c; |
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| 70 | else if (c != EOF && MB_CUR_MAX == 1 && isupper (c)) |
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| 71 | { |
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| 72 | char s[MB_LEN_MAX] = { c, '\0' }; |
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| 73 | wchar_t wc; |
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| 74 | if (mbtowc (&wc, s, 1) >= 0 |
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| 75 | && wctomb (s, (wchar_t) towlower ((wint_t) wc)) == 1) |
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| 76 | c = (unsigned char) s[0]; |
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| 77 | } |
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| 78 | return c; |
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| 79 | #else |
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| 80 | return isupper(c) ? (c) - 'A' + 'a' : c; |
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| 81 | #endif |
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| 82 | } |
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