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<pre> <span class="headline">ctype.h(0P)               POSIX Pro‐
grammer’s  Manual               ctype.h(0P)</span>  </pre> <h2><a
id="PROLOG" href="#PROLOG"></a>PROLOG  &nbsp; &nbsp; &nbsp;  &nb‐
sp;        <a        href="#top_of_page"><span        class="top‐
link">top</span></a></h2><pre>
       This manual page is part of the POSIX Programmer’s Manual.
The Linux
       implementation of this interface may differ (consult the
       corresponding  Linux  manual page for details of Linux be‐
havior), or
       the interface may not be  implemented  on  Linux.   </pre>
<h2><a id="NAME" href="#NAME"></a>NAME  &nbsp; &nbsp; &nbsp; &nb‐
sp;        <a        href="#top_of_page"><span        class="top‐
link">top</span></a></h2><pre>
       ctype.h  —  character  types  </pre>  <h2><a id="SYNOPSIS"
href="#SYNOPSIS"></a>SYNOPSIS  &nbsp;  &nbsp;  &nbsp;  &nbsp;  <a
href="#top_of_page"><span                             class="top‐
link">top</span></a></h2><pre>
       #include &lt;ctype.h&gt;  </pre>  <h2><a  id="DESCRIPTION"
href="#DESCRIPTION"></a>DESCRIPTION   &nbsp; &nbsp; &nbsp; &nbsp;
<a             href="#top_of_page"><span              class="top‐
link">top</span></a></h2><pre>
       Some of the functionality described on this reference page
extends
       the ISO C standard. Applications shall define  the  appro‐
priate feature
       test   macro   (see   the   System  Interfaces  volume  of
POSIX.1‐2008, <i>Section</i>
       <i>2.2</i>, <i>The Compilation Environment</i>) to  enable
the visibility of these
       symbols in this header.

       The  <i>&lt;ctype.h&gt;</i> header shall define the <b>lo‐
cale_t </b>type as described in
       <i>&lt;locale.h&gt;</i>, representing a locale object.

       The following shall be declared as functions and may  also
be defined
       as  macros.  Function prototypes shall be provided for use
with ISO C
       standard compilers.

           <b>int   isalnum(int);</b>
           <b>int   isalnum_l(int, locale_t);</b>
           <b>int   isalpha(int);</b>
           <b>int   isalpha_l(int, locale_t);</b>
           <b>int   isascii(int);</b>
           <b>int   isblank(int);</b>
           <b>int   isblank_l(int, locale_t);</b>
           <b>int   iscntrl(int);</b>
           <b>int   iscntrl_l(int, locale_t);</b>
           <b>int   isdigit(int);</b>
           <b>int   isdigit_l(int, locale_t);</b>
           <b>int   isgraph(int);</b>
           <b>int   isgraph_l(int, locale_t);</b>
           <b>int   islower(int);</b>
           <b>int   islower_l(int, locale_t);</b>
           <b>int   isprint(int);</b>
           <b>int   isprint_l(int, locale_t);</b>
           <b>int   ispunct(int);</b>
           <b>int   ispunct_l(int, locale_t);</b>
           <b>int   isspace(int);</b>
           <b>int   isspace_l(int, locale_t);</b>
           <b>int   isupper(int);</b>
           <b>int   isupper_l(int, locale_t);</b>
           <b>int   isxdigit(int);</b>
           <b>int   isxdigit_l(int, locale_t);</b>
           <b>int   toascii(int);</b>
           <b>int   tolower(int);</b>
           <b>int   tolower_l(int, locale_t);</b>
           <b>int   toupper(int);</b>
           <b>int   toupper_l(int, locale_t);</b>

       The <i>&lt;ctype.h&gt;</i> header shall define the follow‐
ing as macros:

           <b>int   _toupper(int);</b>
           <b>int   _tolower(int);</b>

       <i>The  following  sections  are  informative.</i>  </pre>
<h2><a  id="APPLICATION_USAGE"  href="#APPLICATION_USAGE"></a>AP‐
PLICATION    USAGE     &nbsp;    &nbsp;    &nbsp;    &nbsp;    <a
href="#top_of_page"><span                             class="top‐
link">top</span></a></h2><pre>
       None.     </pre>   <h2><a   id="RATIONALE"   href="#RATIO‐
NALE"></a>RATIONALE    &nbsp;    &nbsp;    &nbsp;    &nbsp;    <a
href="#top_of_page"><span                             class="top‐
link">top</span></a></h2><pre>
       None.   </pre>  <h2><a  id="FUTURE_DIRECTIONS"  href="#FU‐
TURE_DIRECTIONS"></a>FUTURE DIRECTIONS  &nbsp; &nbsp; &nbsp; &nb‐
sp;        <a        href="#top_of_page"><span        class="top‐
link">top</span></a></h2><pre>
       None.     </pre>   <h2><a   id="SEE_ALSO"   href="#SEE_AL‐
SO"></a>SEE   ALSO     &nbsp;    &nbsp;    &nbsp;    &nbsp;    <a
href="#top_of_page"><span                             class="top‐
link">top</span></a></h2><pre>
       <a href="../man0/locale.h.0p.html">locale.h(0p)</a>

       The System Interfaces volume of  POSIX.1‐2008,  <i>Section
2.2</i>, <i>The</i>
       <i>Compilation   Environment</i>,  <a  href="../man3/isal‐
num.3p.html">isalnum(3p)</a>,       <a        href="../man3/isal‐
pha.3p.html">isalpha(3p)</a>,        <a       href="../man3/isas‐
cii.3p.html">isascii(3p)</a>,
       <a   href="../man3/isblank.3p.html">isblank(3p)</a>,    <a
href="../man3/iscntrl.3p.html">iscntrl(3p)</a>,                <a
href="../man3/isdigit.3p.html">isdigit(3p)</a>,                <a
href="../man3/isgraph.3p.html">isgraph(3p)</a>,                <a
href="../man3/islower.3p.html">islower(3p)</a>,
       <a   href="../man3/isprint.3p.html">isprint(3p)</a>,    <a
href="../man3/ispunct.3p.html">ispunct(3p)</a>,                <a
href="../man3/isspace.3p.html">isspace(3p)</a>,                <a
href="../man3/isupper.3p.html">isupper(3p)</a>,                <a
href="../man3/isxdigit.3p.html">isxdigit(3p)</a>,
       <a     href="../man3/mblen.3p.html">mblen(3p)</a>,      <a
href="../man3/mbstowcs.3p.html">mbstowcs(3p)</a>,              <a
href="../man3/mbtowc.3p.html">mbtowc(3p)</a>,                  <a
href="../man3/setlocale.3p.html">setlocale(3p)</a>,            <a
href="../man3/toascii.3p.html">toascii(3p)</a>,
       <a   href="../man3/tolower.3p.html">tolower(3p)</a>,    <a
href="../man3/_tolower.3p.html">_tolower(3p)</a>,              <a
href="../man3/toupper.3p.html">toupper(3p)</a>,                <a
href="../man3/_toupper.3p.html">_toupper(3p)</a>,              <a
href="../man3/wcstombs.3p.html">wcstombs(3p)</a>,
       <a   href="../man3/wctomb.3p.html">wctomb(3p)</a>   </pre>
<h2><a   id="COPYRIGHT"  href="#COPYRIGHT"></a>COPYRIGHT   &nbsp;
&nbsp; &nbsp;  &nbsp;  <a  href="#top_of_page"><span  class="top‐
link">top</span></a></h2><pre>
       Portions  of  this  text  are  reprinted and reproduced in
electronic form
       from IEEE Std 1003.1, 2013 Edition, Standard for  Informa‐
tion
       Technology ‐‐ Portable Operating System Interface (POSIX),
The Open
       Group Base Specifications Issue 7, Copyright (C)  2013  by
the
       Institute of Electrical and Electronics Engineers, Inc and
The Open
       Group.  (This is POSIX.1‐2008 with the 2013 Technical Cor‐
rigendum 1
       applied.)  In  the  event  of any discrepancy between this
version and
       the original IEEE and The Open Group Standard, the  origi‐
nal IEEE and
       The Open Group Standard is the referee document. The orig‐
inal
       Standard    can    be    obtained     online     at     <a
href="http://www.unix.org/online.html">http://www.unix.org/on‐
line.html</a> .

       Any typographical or formatting errors that appear in this
page are
       most  likely to have been introduced during the conversion
of the
       source files to man page format. To  report  such  errors,
see
       <a      href="https://www.kernel.org/doc/man‐pages/report‐
ing_bugs.html">https://www.kernel.org/doc/man‐pages/report‐
ing_bugs.html</a> .

<span  class="footline">IEEE/The  Open Group                 2013
ctype.h(0P)</span> </pre>

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