---
name: "towupper"
section: "3"
platform: "freebsd"
package: "base"
version: "16.0-CURRENT-20261027-61c70dc16a79"
release: "FreeBSD 16.0-CURRENT (2026-10-27)"
platforms: ["linux", "freebsd", "macos"]
url: "https://new.carta.tech/towupper"
---

# towupper(3)

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

## NAME

**towupper** – 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*);

## DESCRIPTION

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

## 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)

## STANDARDS

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