toupper_l

       #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

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.   Other-
       wise,  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 a 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.

RETURN VALUE
       The value returned is that of the converted letter, or c if the conver-
       sion was not possible.

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

       +-------------------------+---------------+---------+
       |Interface                | Attribute     | Value   |
       +-------------------------+---------------+---------+
       |toupper(), tolower(),    | Thread safety | MT-Safe |
       |toupper_l(), tolower_l() |               |         |
       +-------------------------+---------------+---------+
CONFORMING TO
       toupper(), tolower(): C89, C99, 4.3BSD, POSIX.1-2001, POSIX.1-2008.

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

COLOPHON
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       latest    version    of    this    page,    can     be     found     at
       http://www.kernel.org/doc/man-pages/.

GNU                               2015-03-02                        TOUPPER(3)
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