php-doc-en/functions/ctype.xml

 <reference id="ref.ctype">
  <title>Character type functions</title>
  <titleabbrev>ctype</titleabbrev>

  <partintro>
   <para>
    These functions check whether a character or string
    falls into a certain character class according to the
    current locale.
   </para>
   <para>
    When called with an integer argument these functions 
    behave exactly like their C counterparts.
   </para>
   <para>
    When called with a string argument they will check
    every character in the string and will only return
    true if every character in the string matches the
    requested criteria.
   </para>
   <para>
    Passing anything else but a string or integer will 
    return false immediately.
   </para>
   <warning>
    <simpara>
     These functions are new as of PHP 4.0.4 and might change their
     name in the near future.  Suggestions are to change them to
     <function>ctype_issomething</function> instead of
     <function>ctype_something</function> or even to make them part of
     <filename>ext/standard</filename> and use their original C-names,
     although this would possibly lead to further confusion regarding
     the <function>isset</function>
     vs. <function>is_sometype</function> problem.
    </simpara>
   </warning>
  </partintro>


  <refentry id="function.ctype-alnum">
   <refnamediv>
    <refname>ctype_alnum</refname>
    <refpurpose>Check for alphanumeric character(s)</refpurpose>
   </refnamediv>
   <refsect1>
    <title>Description</title>
    <funcsynopsis>
     <funcprototype>
      <funcdef>bool <function>ctype_alnum</function></funcdef>
     <paramdef>string <parameter>c</parameter></paramdef>
     </funcprototype>
    </funcsynopsis>
    <para>
     See also <function>setlocale</function>.
    </para>
   </refsect1>
  </refentry>

  <refentry id="function.ctype-alpha">
   <refnamediv>
    <refname>ctype_alpha</refname>
    <refpurpose>Check for alphabetic character(s)</refpurpose>
   </refnamediv>
   <refsect1>
    <title>Description</title>
    <funcsynopsis>
     <funcprototype>
      <funcdef>bool <function>ctype_alpha</function></funcdef>
     <paramdef>string <parameter>c</parameter></paramdef>
     </funcprototype>
    </funcsynopsis>
    <para>
    </para>
   </refsect1>
  </refentry>

  <refentry id="function.ctype-cntrl">
   <refnamediv>
    <refname>ctype_cntrl</refname>
    <refpurpose>Check for control character(s)</refpurpose>
   </refnamediv>
   <refsect1>
    <title>Description</title>
    <funcsynopsis>
     <funcprototype>
      <funcdef>bool <function>ctype_cntrl</function></funcdef>
     <paramdef>string <parameter>c</parameter></paramdef>
     </funcprototype>
    </funcsynopsis>
    <para>
    </para>
   </refsect1>
  </refentry>

  <refentry id="function.ctype-digit">
   <refnamediv>
    <refname>ctype_digit</refname>
    <refpurpose>Check for numeric character(s)</refpurpose>
   </refnamediv>
   <refsect1>
    <title>Description</title>
    <funcsynopsis>
     <funcprototype>
      <funcdef>bool <function>ctype_digit</function></funcdef>
     <paramdef>string <parameter>c</parameter></paramdef>
     </funcprototype>
    </funcsynopsis>
    <para>
    </para>
   </refsect1>
  </refentry>

  <refentry id="function.ctype-lower">
   <refnamediv>
    <refname>ctype_lower</refname>
    <refpurpose>Check for lowercase character(s)</refpurpose>
   </refnamediv>
   <refsect1>
    <title>Description</title>
    <funcsynopsis>
     <funcprototype>
      <funcdef>bool <function>ctype_lower</function></funcdef>
     <paramdef>string <parameter>c</parameter></paramdef>
     </funcprototype>
    </funcsynopsis>
    <para>
    </para>
   </refsect1>
  </refentry>

  <refentry id="function.ctype-graph">
   <refnamediv>
    <refname>ctype_graph</refname>
    <refpurpose>Check for any printable character(s) except space</refpurpose>
   </refnamediv>
   <refsect1>
    <title>Description</title>
    <funcsynopsis>
     <funcprototype>
      <funcdef>bool <function>ctype_graph</function></funcdef>
     <paramdef>string <parameter>c</parameter></paramdef>
     </funcprototype>
    </funcsynopsis>
    <para>
    </para>
   </refsect1>
  </refentry>

  <refentry id="function.ctype-print">
   <refnamediv>
    <refname>ctype_print</refname>
    <refpurpose>Check for printable character(s)</refpurpose>
   </refnamediv>
   <refsect1>
    <title>Description</title>
    <funcsynopsis>
     <funcprototype>
      <funcdef>bool <function>ctype_print</function></funcdef>
     <paramdef>string <parameter>c</parameter></paramdef>
     </funcprototype>
    </funcsynopsis>
    <para>
    </para>
   </refsect1>
  </refentry>

  <refentry id="function.ctype-punct">
   <refnamediv>
    <refname>ctype_punct</refname>
    <refpurpose>
     Check for any printable character which is not whitespace or an
     alphanumeric character
    </refpurpose>
   </refnamediv>
   <refsect1>
    <title>Description</title>
    <funcsynopsis>
     <funcprototype>
      <funcdef>bool <function>ctype_punct</function></funcdef>
     <paramdef>string <parameter>c</parameter></paramdef>
     </funcprototype>
    </funcsynopsis>
    <para>
    </para>
   </refsect1>
  </refentry>

  <refentry id="function.ctype-space">
   <refnamediv>
    <refname>ctype_space</refname>
    <refpurpose>Check for whitespace character(s)</refpurpose>
   </refnamediv>
   <refsect1>
    <title>Description</title>
    <funcsynopsis>
     <funcprototype>
      <funcdef>bool <function>ctype_space</function></funcdef>
     <paramdef>string <parameter>c</parameter></paramdef>
     </funcprototype>
    </funcsynopsis>
    <para>
    </para>
   </refsect1>
  </refentry>

  <refentry id="function.ctype-upper">
   <refnamediv>
    <refname>ctype_upper</refname>
    <refpurpose>Check for uppercase character(s)</refpurpose>
   </refnamediv>
   <refsect1>
    <title>Description</title>
    <funcsynopsis>
     <funcprototype>
      <funcdef>bool <function>ctype_upper</function></funcdef>
     <paramdef>string <parameter>c</parameter></paramdef>
     </funcprototype>
    </funcsynopsis>
    <para>
    </para>
   </refsect1>
  </refentry>

  <refentry id="function.ctype-xdigit">
   <refnamediv>
    <refname>ctype_xdigit</refname>
    <refpurpose>
     Check for character(s) representing a hexadecimal digit
    </refpurpose>
   </refnamediv>
   <refsect1>
    <title>Description</title>
    <funcsynopsis>
     <funcprototype>
      <funcdef>bool <function>ctype_xdigit</function></funcdef>
     <paramdef>string <parameter>c</parameter></paramdef>
     </funcprototype>
    </funcsynopsis>
    <para>
    </para>
   </refsect1>
  </refentry>

 </reference>

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