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>XVII. Character Type Functions</H1
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NAME="AEN23693"
></A
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><H1
CLASS="section"
><A
NAME="ctype.intro"
>简介</A
></H1
><P
> The functions provided by this extension check whether a character
or string falls into a certain character class according to the
current locale (see also <A
HREF="function.setlocale.html"
><B
CLASS="function"
>setlocale()</B
></A
>).
</P
><P
> When called with an integer argument these functions
behave exactly like their C counterparts from
<TT
CLASS="filename"
>ctype.h</TT
>.
It means that if you pass an integer smaller than 256 it will use the
ASCII value of it to see if it fits in the specified range (digits are in
0x30-0x39). If the number is between -128 and -1 inclusive then 256 will
be added and the check will be done on that.
</P
><P
> When called with a string argument they will check
every character in the string and will only return
<TT
CLASS="constant"
><B
>TRUE</B
></TT
> if every character in the string matches the
requested criteria. When called with an empty string
the result will always be <TT
CLASS="constant"
><B
>TRUE</B
></TT
> in PHP < 5.1 and <TT
CLASS="constant"
><B
>FALSE</B
></TT
> since 5.1.
</P
><P
> Passing anything else but a string or integer will
return <TT
CLASS="constant"
><B
>FALSE</B
></TT
> immediately.
</P
><P
> It should be noted that ctype functions are always preferred over
regular expressions, and even to some equivalent str_* and is_* functions.
This is because of the fact that ctype uses a native C library and thus
processes significantly faster.
</P
></DIV
><DIV
CLASS="section"
><H1
CLASS="section"
><A
NAME="ctype.requirements"
>需求</A
></H1
><P
> None besides functions from the standard C library which are
always available.
</P
></DIV
><DIV
CLASS="section"
><H1
CLASS="section"
><A
NAME="ctype.installation"
>安装</A
></H1
><P
> Beginning with PHP 4.2.0 these functions are enabled by default.
For older versions you have to configure and compile PHP with
<CODE
CLASS="option"
>--enable-ctype</CODE
>. You can disable
ctype support with <CODE
CLASS="option"
>--disable-ctype</CODE
>.
</P
><P
> <TT
CLASS="literal"
>PHP</TT
> 的 Windows
版本已经内置该扩展模块的支持。无需加载任何附加扩展库即可使用这些函数。</P
><DIV
CLASS="note"
><BLOCKQUOTE
CLASS="note"
><P
><B
>注意: </B
>
Builtin support for ctype is available with PHP 4.3.0.
</P
></BLOCKQUOTE
></DIV
></DIV
><DIV
CLASS="section"
><H1
CLASS="section"
><A
NAME="ctype.configuration"
>运行时配置</A
></H1
><P
>本扩展模块在 <TT
CLASS="filename"
>php.ini</TT
> 中未定义任何配置选项。</P
></DIV
><DIV
CLASS="section"
><H1
CLASS="section"
><A
NAME="ctype.resources"
>资源类型</A
></H1
><P
>本扩展模块未定义任何资源类型。</P
></DIV
><DIV
CLASS="section"
><H1
CLASS="section"
><A
NAME="ctype.constants"
>预定义常量</A
></H1
><P
>本扩展模块未定义任何常量。</P
></DIV
></DIV
><DIV
CLASS="TOC"
><DL
><DT
><B
>目录</B
></DT
><DT
><A
HREF="function.ctype-alnum.html"
>ctype_alnum</A
> -- Check for alphanumeric character(s)</DT
><DT
><A
HREF="function.ctype-alpha.html"
>ctype_alpha</A
> -- Check for alphabetic character(s)</DT
><DT
><A
HREF="function.ctype-cntrl.html"
>ctype_cntrl</A
> -- Check for control character(s)</DT
><DT
><A
HREF="function.ctype-digit.html"
>ctype_digit</A
> -- Check for numeric character(s)</DT
><DT
><A
HREF="function.ctype-graph.html"
>ctype_graph</A
> -- Check for any printable character(s) except space</DT
><DT
><A
HREF="function.ctype-lower.html"
>ctype_lower</A
> -- Check for lowercase character(s)</DT
><DT
><A
HREF="function.ctype-print.html"
>ctype_print</A
> -- Check for printable character(s)</DT
><DT
><A
HREF="function.ctype-punct.html"
>ctype_punct</A
> --
Check for any printable character which is not whitespace or an
alphanumeric character
</DT
><DT
><A
HREF="function.ctype-space.html"
>ctype_space</A
> -- Check for whitespace character(s)</DT
><DT
><A
HREF="function.ctype-upper.html"
>ctype_upper</A
> -- Check for uppercase character(s)</DT
><DT
><A
HREF="function.ctype-xdigit.html"
>ctype_xdigit</A
> --
Check for character(s) representing a hexadecimal digit
</DT
></DL
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