| <html lang="en"> |
| <head> |
| <title>Non-reentrant String Conversion - The GNU C Library</title> |
| <meta http-equiv="Content-Type" content="text/html"> |
| <meta name="description" content="The GNU C Library"> |
| <meta name="generator" content="makeinfo 4.13"> |
| <link title="Top" rel="start" href="index.html#Top"> |
| <link rel="up" href="Non_002dreentrant-Conversion.html#Non_002dreentrant-Conversion" title="Non-reentrant Conversion"> |
| <link rel="prev" href="Non_002dreentrant-Character-Conversion.html#Non_002dreentrant-Character-Conversion" title="Non-reentrant Character Conversion"> |
| <link rel="next" href="Shift-State.html#Shift-State" title="Shift State"> |
| <link href="http://www.gnu.org/software/texinfo/" rel="generator-home" title="Texinfo Homepage"> |
| <!-- |
| This file documents the GNU C library. |
| |
| This is Edition 0.12, last updated 2007-10-27, |
| of `The GNU C Library Reference Manual', for version |
| 2.8 (Sourcery G++ Lite 2011.03-41). |
| |
| Copyright (C) 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2001, 2002, |
| 2003, 2007, 2008, 2010 Free Software Foundation, Inc. |
| |
| Permission is granted to copy, distribute and/or modify this document |
| under the terms of the GNU Free Documentation License, Version 1.3 or |
| any later version published by the Free Software Foundation; with the |
| Invariant Sections being ``Free Software Needs Free Documentation'' |
| and ``GNU Lesser General Public License'', the Front-Cover texts being |
| ``A GNU Manual'', and with the Back-Cover Texts as in (a) below. A |
| copy of the license is included in the section entitled "GNU Free |
| Documentation License". |
| |
| (a) The FSF's Back-Cover Text is: ``You have the freedom to |
| copy and modify this GNU manual. Buying copies from the FSF |
| supports it in developing GNU and promoting software freedom.''--> |
| <meta http-equiv="Content-Style-Type" content="text/css"> |
| <style type="text/css"><!-- |
| pre.display { font-family:inherit } |
| pre.format { font-family:inherit } |
| pre.smalldisplay { font-family:inherit; font-size:smaller } |
| pre.smallformat { font-family:inherit; font-size:smaller } |
| pre.smallexample { font-size:smaller } |
| pre.smalllisp { font-size:smaller } |
| span.sc { font-variant:small-caps } |
| span.roman { font-family:serif; font-weight:normal; } |
| span.sansserif { font-family:sans-serif; font-weight:normal; } |
| --></style> |
| <link rel="stylesheet" type="text/css" href="../cs.css"> |
| </head> |
| <body> |
| <div class="node"> |
| <a name="Non-reentrant-String-Conversion"></a> |
| <a name="Non_002dreentrant-String-Conversion"></a> |
| <p> |
| Next: <a rel="next" accesskey="n" href="Shift-State.html#Shift-State">Shift State</a>, |
| Previous: <a rel="previous" accesskey="p" href="Non_002dreentrant-Character-Conversion.html#Non_002dreentrant-Character-Conversion">Non-reentrant Character Conversion</a>, |
| Up: <a rel="up" accesskey="u" href="Non_002dreentrant-Conversion.html#Non_002dreentrant-Conversion">Non-reentrant Conversion</a> |
| <hr> |
| </div> |
| |
| <h4 class="subsection">6.4.2 Non-reentrant Conversion of Strings</h4> |
| |
| <p>For convenience the ISO C90<!-- /@w --> standard also defines functions to |
| convert entire strings instead of single characters. These functions |
| suffer from the same problems as their reentrant counterparts from |
| Amendment 1<!-- /@w --> to ISO C90<!-- /@w -->; see <a href="Converting-Strings.html#Converting-Strings">Converting Strings</a>. |
| |
| <!-- stdlib.h --> |
| <!-- ISO --> |
| <div class="defun"> |
| — Function: size_t <b>mbstowcs</b> (<var>wchar_t *wstring, const char *string, size_t size</var>)<var><a name="index-mbstowcs-666"></a></var><br> |
| <blockquote><p>The <code>mbstowcs</code> (“multibyte string to wide character string”) |
| function converts the null-terminated string of multibyte characters |
| <var>string</var> to an array of wide character codes, storing not more than |
| <var>size</var> wide characters into the array beginning at <var>wstring</var>. |
| The terminating null character counts towards the size, so if <var>size</var> |
| is less than the actual number of wide characters resulting from |
| <var>string</var>, no terminating null character is stored. |
| |
| <p>The conversion of characters from <var>string</var> begins in the initial |
| shift state. |
| |
| <p>If an invalid multibyte character sequence is found, the <code>mbstowcs</code> |
| function returns a value of -1. Otherwise, it returns the number |
| of wide characters stored in the array <var>wstring</var>. This number does |
| not include the terminating null character, which is present if the |
| number is less than <var>size</var>. |
| |
| <p>Here is an example showing how to convert a string of multibyte |
| characters, allocating enough space for the result. |
| |
| <pre class="smallexample"> wchar_t * |
| mbstowcs_alloc (const char *string) |
| { |
| size_t size = strlen (string) + 1; |
| wchar_t *buf = xmalloc (size * sizeof (wchar_t)); |
| |
| size = mbstowcs (buf, string, size); |
| if (size == (size_t) -1) |
| return NULL; |
| buf = xrealloc (buf, (size + 1) * sizeof (wchar_t)); |
| return buf; |
| } |
| </pre> |
| </blockquote></div> |
| |
| <!-- stdlib.h --> |
| <!-- ISO --> |
| <div class="defun"> |
| — Function: size_t <b>wcstombs</b> (<var>char *string, const wchar_t *wstring, size_t size</var>)<var><a name="index-wcstombs-667"></a></var><br> |
| <blockquote><p>The <code>wcstombs</code> (“wide character string to multibyte string”) |
| function converts the null-terminated wide character array <var>wstring</var> |
| into a string containing multibyte characters, storing not more than |
| <var>size</var> bytes starting at <var>string</var>, followed by a terminating |
| null character if there is room. The conversion of characters begins in |
| the initial shift state. |
| |
| <p>The terminating null character counts towards the size, so if <var>size</var> |
| is less than or equal to the number of bytes needed in <var>wstring</var>, no |
| terminating null character is stored. |
| |
| <p>If a code that does not correspond to a valid multibyte character is |
| found, the <code>wcstombs</code> function returns a value of -1. |
| Otherwise, the return value is the number of bytes stored in the array |
| <var>string</var>. This number does not include the terminating null character, |
| which is present if the number is less than <var>size</var>. |
| </p></blockquote></div> |
| |
| </body></html> |
| |
