locale/FreeBSD/isdigit.3

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  36 .\"     @(#)isdigit.3   8.1 (Berkeley) 6/4/93
  37 .\" $FreeBSD: src/lib/libc/locale/isdigit.3,v 1.19 2004/08/21 07:37:08 tjr Exp $
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  39 .Dd August 21, 2004
  40 .Dt ISDIGIT 3
  41 .Os
  42 .Sh NAME
  43 .Nm isdigit, isnumber
  44 .Nd decimal-digit character test
  45 .Sh LIBRARY
  46 .Lb libc
  47 .Sh SYNOPSIS
  48 .In ctype.h
  49 .Ft int
  50 .Fn isdigit "int c"
  51 .Ft int
  52 .Fn isnumber "int c"
  53 .Sh DESCRIPTION
  54 The
  55 .Fn isdigit
  56 function tests for a decimal digit character.
  57 Regardless of locale, this includes the following characters only:
  58 .Pp
  59 .Bl -column \&``0''______ \&``0''______ \&``0''______ \&``0''______ \&``0''______
  60 .It "\&``0''\t``1''\t``2''\t``3''\t``4''"
  61 .It "\&``5''\t``6''\t``7''\t``8''\t``9''"
  62 .El
  63 .Pp
  64 The
  65 .Fn isnumber
  66 function behaves similarly to
  67 .Fn isdigit ,
  68 but may recognize additional characters, depending on the current locale
  69 setting.
  70 .Pp
  71 For single C
  72 .Va char Ns s
  73 locales (see
  74 .Xr multibyte 3 )
  75 the value of the argument is
  76 representable as an
  77 .Li unsigned char
  78 or the value of
  79 .Dv EOF .
  80 .Sh RETURN VALUES
  81 The
  82 .Fn isdigit
  83 and
  84 .Fn isnumber
  85 functions return zero if the character tests false and
  86 returns non-zero if the character tests true.
  87 .Sh COMPATIBILITY
  88 The
  89 .Bx 4.4
  90 extension of accepting arguments outside of the range of the
  91 .Vt "unsigned char"
  92 type in locales with large character sets is considered obsolete
  93 and may not be supported in future releases.
  94 The
  95 .Fn iswdigit
  96 function should be used instead.
  97 .Sh SEE ALSO
  98 .Xr ctype 3 ,
  99 .Xr iswdigit 3 ,
 100 .Xr multibyte 3 ,
 101 .Xr ascii 7
 102 .Sh STANDARDS
 103 The
 104 .Fn isdigit
 105 function conforms to
 106 .St -isoC .
 107 .Sh HISTORY
 108 The
 109 .Fn isnumber
 110 function appeared in
 111 .Bx 4.4 .