newlib-cygwin/newlib/libc/string/wcwidth.c

54 lines
1.3 KiB
C

/*
FUNCTION
<<wcwidth>>---number of column positions of a wide-character code
INDEX
wcwidth
ANSI_SYNOPSIS
#include <wchar.h>
int wcwidth(const wchar_t <[wc]>);
TRAD_SYNOPSIS
#include <wchar.h>
int wcwidth(<[wc]>)
wchar_t *<[wc]>;
DESCRIPTION
The <<wcwidth>> function shall determine the number of column
positions required for the wide character <[wc]>. The application
shall ensure that the value of <[wc]> is a character representable
as a wchar_t, and is a wide-character code corresponding to a
valid character in the current locale.
RETURNS
The <<wcwidth>> function shall either return 0 (if <[wc]> is a null
wide-character code), or return the number of column positions to
be occupied by the wide-character code <[wc]>, or return -1 (if <[wc]>
does not correspond to a printable wide-character code).
The current implementation of <<wcwidth>> simply sets the width
of all printable characters to 1 since newlib has no character
tables around.
PORTABILITY
<<wcwidth>> has been introduced in the Single UNIX Specification Volume 2.
<<wcwidth>> has been marked as an extension in the Single UNIX Specification Volume 3.
*/
#include <_ansi.h>
#include <wchar.h>
#include <wctype.h>
int
_DEFUN (wcwidth, (wc),
_CONST wchar_t wc)
{
if (iswprint (wc))
return 1;
if (iswcntrl (wc) || wc == L'\0')
return 0;
return -1;
}