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   toupper_l    ( 3 )

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Имя (Name)

toupper, tolower, toupper_l, tolower_l - convert uppercase or
       lowercase

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Синопсис (Synopsis)

#include <ctype.h>

       int toupper(int c);
       int tolower(int c);

       int toupper_l(int c, locale_t locale);
       int tolower_l(int c, locale_t locale);

   Feature Test Macro Requirements for glibc (see
   feature_test_macros(7)):

       toupper_l(), tolower_l():
           Since glibc 2.10:
               _XOPEN_SOURCE >= 700
           Before glibc 2.10:
               _GNU_SOURCE

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Описание (Description)

These functions convert lowercase letters to uppercase, and vice
       versa.

       If c is a lowercase letter, toupper() returns its uppercase
       equivalent, if an uppercase representation exists in the current
       locale.  Otherwise, it returns c.  The toupper_l() function
       performs the same task, but uses the locale referred to by the
       locale handle locale.

       If c is an uppercase letter, tolower() returns its lowercase
       equivalent, if a lowercase representation exists in the current
       locale.  Otherwise, it returns c.  The tolower_l() function
       performs the same task, but uses the locale referred to by the
       locale handle locale.

       If c is neither an unsigned char value nor EOF, the behavior of
       these functions is undefined.

       The behavior of toupper_l() and tolower_l() is undefined if
       locale is the special locale object LC_GLOBAL_LOCALE (see
       duplocale(3)) or is not a valid locale object handle.

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Возвращаемое значение (Return value)

The value returned is that of the converted letter, or c if the
       conversion was not possible.

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Атрибуты (Attributes)

For an explanation of the terms used in this section, see
       attributes(7).

       ┌──────────────────────────────────────┬───────────────┬─────────┐
       │Interface                             │ Attribute     │ Value   │
       ├──────────────────────────────────────┼───────────────┼─────────┤
       │toupper(), tolower(), toupper_l(),    │ Thread safety │ MT-Safe │
       │tolower_l()                           │               │         │
       └──────────────────────────────────────┴───────────────┴─────────┘

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Стандарты (Conforming to)

toupper(), tolower(): C89, C99, 4.3BSD, POSIX.1-2001,
       POSIX.1-2008.

       toupper_l(), tolower_l(): POSIX.1-2008.

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Примечание (Note)

The standards require that the argument c for these functions is
       either EOF or a value that is representable in the type unsigned
       char.  If the argument c is of type char, it must be cast to
       unsigned char, as in the following example:

           char c;
           ...
           res = toupper((unsigned char) c);

       This is necessary because char may be the equivalent signed char,
       in which case a byte where the top bit is set would be sign
       extended when converting to int, yielding a value that is outside
       the range of unsigned char.

       The details of what constitutes an uppercase or lowercase letter
       depend on the locale.  For example, the default "C" locale does
       not know about umlauts, so no conversion is done for them.

       In some non-English locales, there are lowercase letters with no
       corresponding uppercase equivalent; the German sharp s is one
       example.

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Смотри также (See also)

isalpha(3), newlocale(3), setlocale(3), towlower(3), towupper(3),
       uselocale(3), locale(7)

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