1<html lang="en"> 2<head> 3<title>ungetwc - Untitled</title> 4<meta http-equiv="Content-Type" content="text/html"> 5<meta name="description" content="Untitled"> 6<meta name="generator" content="makeinfo 4.13"> 7<link title="Top" rel="start" href="index.html#Top"> 8<link rel="up" href="Stdio.html#Stdio" title="Stdio"> 9<link rel="prev" href="ungetc.html#ungetc" title="ungetc"> 10<link rel="next" href="vfprintf.html#vfprintf" title="vfprintf"> 11<link href="http://www.gnu.org/software/texinfo/" rel="generator-home" title="Texinfo Homepage"> 12<meta http-equiv="Content-Style-Type" content="text/css"> 13<style type="text/css"><!-- 14 pre.display { font-family:inherit } 15 pre.format { font-family:inherit } 16 pre.smalldisplay { font-family:inherit; font-size:smaller } 17 pre.smallformat { font-family:inherit; font-size:smaller } 18 pre.smallexample { font-size:smaller } 19 pre.smalllisp { font-size:smaller } 20 span.sc { font-variant:small-caps } 21 span.roman { font-family:serif; font-weight:normal; } 22 span.sansserif { font-family:sans-serif; font-weight:normal; } 23--></style> 24<link rel="stylesheet" type="text/css" href="../cs.css"> 25</head> 26<body> 27<div class="node"> 28<a name="ungetwc"></a> 29<p> 30Next: <a rel="next" accesskey="n" href="vfprintf.html#vfprintf">vfprintf</a>, 31Previous: <a rel="previous" accesskey="p" href="ungetc.html#ungetc">ungetc</a>, 32Up: <a rel="up" accesskey="u" href="Stdio.html#Stdio">Stdio</a> 33<hr> 34</div> 35 36<h3 class="section">4.67 <code>ungetwc</code>—push wide character data back into a stream</h3> 37 38<p><a name="index-ungetwc-323"></a><a name="index-g_t_005fungetwc_005fr-324"></a><strong>Synopsis</strong> 39<pre class="example"> #include <stdio.h> 40 #include <wchar.h> 41 wint_t ungetwc(wint_t <var>wc</var>, FILE *<var>stream</var>); 42 43 wint_t _ungetwc_r(struct _reent *<var>reent</var>, wint_t <var>wc</var>, FILE *<var>stream</var>); 44 45</pre> 46 <p><strong>Description</strong><br> 47<code>ungetwc</code> is used to return wide characters back to <var>stream</var> to be 48read again. If <var>wc</var> is WEOF, the stream is unchanged. Otherwise, the 49wide character <var>wc</var> is put back on the stream, and subsequent reads will see 50the wide chars pushed back in reverse order. Pushed wide chars are lost if the 51stream is repositioned, such as by <code>fseek</code>, <code>fsetpos</code>, or 52<code>rewind</code>. 53 54 <p>The underlying file is not changed, but it is possible to push back 55something different than what was originally read. Ungetting a 56character will clear the end-of-stream marker, and decrement the file 57position indicator. Pushing back beyond the beginning of a file gives 58unspecified behavior. 59 60 <p>The alternate function <code>_ungetwc_r</code> is a reentrant version. The 61extra argument <var>reent</var> is a pointer to a reentrancy structure. 62 63 <p><br> 64<strong>Returns</strong><br> 65The wide character pushed back, or <code>WEOF</code> on error. 66 67 <p><br> 68<strong>Portability</strong><br> 69C99 70 71 <p><br> 72 73 </body></html> 74 75