### 6.27 `wcswidth`—number of column positions of a wide-character string

Synopsis

    #include <wchar.h>
    int wcswidth(const wchar_t *pwcs, size_t n);

Description
The `wcswidth` function shall determine the number of column positions required for n wide-character codes (or fewer than n wide-character codes if a null wide-character code is encountered before n wide-character codes are exhausted) in the string pointed to by pwcs.

Returns
The `wcswidth` function either shall return 0 (if pwcs points to a null wide-character code), or return the number of column positions to be occupied by the wide-character string pointed to by pwcs, or return -1 (if any of the first n wide-character codes in the wide-character string pointed to by pwcs is not a printable wide-character code).

Portability
`wcswidth` has been introduced in the Single UNIX Specification Volume 2. `wcswidth` has been marked as an extension in the Single UNIX Specification Volume 3.