man3/wcwidth.3

   1 .\" Copyright (c) Bruno Haible <haible@clisp.cons.org>
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  10 .\" References consulted:
  11 .\"   GNU glibc-2 source code and manual
  12 .\"   Dinkumware C library reference http://www.dinkumware.com/
  13 .\"   OpenGroup's Single UNIX specification http://www.UNIX-systems.org/online.html
  14 .\"
  15 .TH WCWIDTH 3  2017-09-15 "GNU" "Linux Programmer's Manual"
  16 .SH NAME
  17 wcwidth \- determine columns needed for a wide character
  18 .SH SYNOPSIS
  19 .nf
  20 .BR "#define _XOPEN_SOURCE" "       /* See feature_test_macros(7) */"
  21 .B #include <wchar.h>
  22 .PP
  23 .BI "int wcwidth(wchar_t " c );
  24 .fi
  25 .SH DESCRIPTION
  26 The
  27 .BR wcwidth ()
  28 function returns the number of columns
  29 needed to represent the wide character
  30 .IR c .
  31 If
  32 .I c
  33 is a printable wide character, the value
  34 is at least 0.
  35 If
  36 .I c
  37 is null wide character (L\(aq\\0\(aq), the value is 0.
  38 Otherwise, \-1 is returned.
  39 .SH RETURN VALUE
  40 The
  41 .BR wcwidth ()
  42 function returns the number of
  43 column positions for
  44 .IR c .
  45 .SH ATTRIBUTES
  46 For an explanation of the terms used in this section, see
  47 .BR attributes (7).
  48 .TS
  49 allbox;
  50 lb lb lb
  51 l l l.
  52 Interface       Attribute       Value
  53 T{
  54 .BR wcwidth ()
  55 T}      Thread safety   MT-Safe locale
  56 .TE
  57 .SH CONFORMING TO
  58 POSIX.1-2001, POSIX.1-2008.
  59 .PP
  60 Note that glibc before 2.2.5 used the prototype
  61 .PP
  62 .nf
  63 .BI "int wcwidth(wint_t " c );
  64 .fi
  65 .SH NOTES
  66 The behavior of
  67 .BR wcwidth ()
  68 depends on the
  69 .B LC_CTYPE
  70 category of the
  71 current locale.
  72 .SH SEE ALSO
  73 .BR iswprint (3),
  74 .BR wcswidth (3)