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towupper(3) — Linux manual page

towupper(3)              Library Functions Manualtowupper(3)

NAME        top

       towupper, towupper_l - convert a wide character to uppercase

LIBRARY        top

       Standard C library (libc,-lc)

SYNOPSIS        top

#include <wctype.h>wint_t towupper(wint_twc);wint_t towupper_l(wint_twc, locale_tlocale);   Feature Test Macro Requirements for glibc (seefeature_test_macros(7)):towupper_l():           Since glibc 2.10:               _XOPEN_SOURCE >= 700           Before glibc 2.10:               _GNU_SOURCE

DESCRIPTION        top

       Thetowupper() function is the wide-character equivalent of thetoupper(3) function.  Ifwc is a lowercase wide character, and       there exists an uppercase equivalent in the current locale, it       returns the uppercase equivalent ofwc.  In all other cases,wc is       returned unchanged.       Thetowupper_l() function performs the same task, but performs the       conversion based on the character type information in the locale       specified bylocale.  The behavior oftowupper_l() is undefined iflocale is the special locale objectLC_GLOBAL_LOCALE(seeduplocale(3)) or is not a valid locale object handle.       The argumentwc must be representable as awchar_t and be a valid       character in the locale or be the valueWEOF.

RETURN VALUE        top

       Ifwc was convertible to uppercase,towupper() returns its       uppercase equivalent; otherwise it returnswc.

ATTRIBUTES        top

       For an explanation of the terms used in this section, seeattributes(7).       ┌───────────────────────────────┬───────────────┬────────────────┐       │Interface│Attribute│Value│       ├───────────────────────────────┼───────────────┼────────────────┤       │towupper()                    │ Thread safety │ MT-Safe locale │       ├───────────────────────────────┼───────────────┼────────────────┤       │towupper_l()                  │ Thread safety │ MT-Safe        │       └───────────────────────────────┴───────────────┴────────────────┘

STANDARDS        top

towupper()              C11, POSIX.1-2008 (XSI).towupper_l()              POSIX.1-2008.

HISTORY        top

towupper()              C99, POSIX.1-2001 (XSI).  Obsolete in POSIX.1-2008 (XSI).towupper_l()              POSIX.1-2008.  glibc 2.3.

NOTES        top

       The behavior of these functions depends on theLC_CTYPEcategory       of the locale.       These functions are not very appropriate for dealing with Unicode       characters, because Unicode knows about three cases: upper, lower,       and title case.

SEE ALSO        top

iswupper(3),towctrans(3),towlower(3),locale(7)

COLOPHON        top

       This page is part of theman-pages (Linux kernel and C library       user-space interface documentation) project.  Information about       the project can be found at        ⟨https://www.kernel.org/doc/man-pages/⟩.  If you have a bug report       for this manual page, see       ⟨https://git.kernel.org/pub/scm/docs/man-pages/man-pages.git/tree/CONTRIBUTING⟩.       This page was obtained from the tarball man-pages-6.15.tar.gz       fetched from       ⟨https://mirrors.edge.kernel.org/pub/linux/docs/man-pages/⟩ on       2025-08-11.  If you discover any rendering problems in this HTML       version of the page, or you believe there is a better or more up-       to-date source for the page, or you have corrections or       improvements to the information in this COLOPHON (which isnot       part of the original manual page), send a mail to       man-pages@man7.orgLinux man-pages 6.15            2025-05-17towupper(3)

Pages that refer to this page:iswupper(3), toupper(3), towctrans(3), towlower(3), wcscasecmp(3)

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