---
name: "towupper"
section: "3"
platform: "macos"
package: "Libc"
version: "1752.120.2"
release: "macOS 26.5"
platforms: ["linux", "freebsd", "macos"]
url: "https://new.carta.tech/towupper"
---

# towupper(3)

lower case to upper case letter conversion (wide character version)

## NAME

**towupper**, **towupper\_l** – lower case to upper case letter conversion (wide character version)

## LIBRARY

Standard C Library (libc, -lc)

## SYNOPSIS

**#include \<wctype.h\>**

*wint\_t*\

**towupper**(*wint\_t wc*);

**#include \<wctype.h\>**

**#include \<xlocale.h\>**

*wint\_t*\

**towupper\_l**(*wint\_t wc*, *locale\_t loc*);

## DESCRIPTION

The **towupper**() function converts a lower-case letter to the corresponding upper-case letter.

Although the **towupper**() function uses the current locale, the **towupper\_l**() function may be passed a locale directly. See [xlocale(3)](/xlocale/3.md) for more information.

## RETURN VALUES

If the argument is a lower-case letter, the **towupper**() function returns the corresponding upper-case letter if there is one; otherwise, the argument is returned unchanged.

## SEE ALSO

[iswupper(3)](/iswupper/3.md), [toupper(3)](/toupper/3.md), [towlower(3)](/towlower/3.md), [wctrans(3)](/wctrans/3.md), [xlocale(3)](/xlocale/3.md)

## STANDARDS

The **towupper**() function conforms to ISO/IEC 9899:1999 (“ISO C99”).