<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html401/loose.dtd"> <html> <!-- Created on July, 8 2015 by texi2html 1.78a --> <!-- Written by: Lionel Cons <Lionel.Cons@cern.ch> (original author) Karl Berry <karl@freefriends.org> Olaf Bachmann <obachman@mathematik.uni-kl.de> and many others. Maintained by: Many creative people. Send bugs and suggestions to <texi2html-bug@nongnu.org> --> <head> <title>GNU libunistring: 2. Conventions</title> <meta name="description" content="GNU libunistring: 2. Conventions"> <meta name="keywords" content="GNU libunistring: 2. Conventions"> <meta name="resource-type" content="document"> <meta name="distribution" content="global"> <meta name="Generator" content="texi2html 1.78a"> <meta http-equiv="Content-Type" content="text/html; charset=utf-8"> <style type="text/css"> <!-- a.summary-letter {text-decoration: none} pre.display {font-family: serif} pre.format {font-family: serif} pre.menu-comment {font-family: serif} pre.menu-preformatted {font-family: serif} pre.smalldisplay {font-family: serif; font-size: smaller} pre.smallexample {font-size: smaller} pre.smallformat {font-family: serif; font-size: smaller} pre.smalllisp {font-size: smaller} span.roman {font-family:serif; font-weight:normal;} span.sansserif {font-family:sans-serif; font-weight:normal;} ul.toc {list-style: none} --> </style> </head> <body lang="en" bgcolor="#FFFFFF" text="#000000" link="#0000FF" vlink="#800080" alink="#FF0000"> <table cellpadding="1" cellspacing="1" border="0"> <tr><td valign="middle" align="left">[<a href="libunistring_1.html#SEC1" title="Beginning of this chapter or previous chapter"> << </a>]</td> <td valign="middle" align="left">[<a href="libunistring_3.html#SEC10" title="Next chapter"> >> </a>]</td> <td valign="middle" align="left"> </td> <td valign="middle" align="left"> </td> <td valign="middle" align="left"> </td> <td valign="middle" align="left"> </td> <td valign="middle" align="left"> </td> <td valign="middle" align="left">[<a href="libunistring.html#SEC_Top" title="Cover (top) of document">Top</a>]</td> <td valign="middle" align="left">[<a href="libunistring.html#SEC_Contents" title="Table of contents">Contents</a>]</td> <td valign="middle" align="left">[<a href="libunistring_19.html#SEC77" title="Index">Index</a>]</td> <td valign="middle" align="left">[<a href="libunistring_abt.html#SEC_About" title="About (help)"> ? </a>]</td> </tr></table> <hr size="2"> <a name="Conventions"></a> <a name="SEC9"></a> <h1 class="chapter"> <a href="libunistring.html#TOC9">2. Conventions</a> </h1> <p>This chapter explains conventions valid throughout the libunistring library. </p> <a name="IDX14"></a> <p>Variables of type <code>char *</code> denote C strings in locale encoding. See <a href="libunistring_1.html#SEC4">Locale encodings</a>. </p> <p>Variables of type <code>uint8_t *</code> denote UTF-8 strings. Their units are bytes. </p> <p>Variables of type <code>uint16_t *</code> denote UTF-16 strings, without byte order mark. Their units are 2-byte words. </p> <p>Variables of type <code>uint32_t *</code> denote UTF-32 strings, without byte order mark. Their units are 4-byte words. </p> <p>Argument pairs <code>(<var>s</var>, <var>n</var>)</code> denote a string <code><var>s</var>[0..<var>n</var>-1]</code> with exactly <var>n</var> units. </p> <p>All functions with prefix ‘<samp>ulc_</samp>’ operate on C strings in locale encoding. </p> <p>All functions with prefix ‘<samp>u8_</samp>’ operate on UTF-8 strings. </p> <p>All functions with prefix ‘<samp>u16_</samp>’ operate on UTF-16 strings. </p> <p>All functions with prefix ‘<samp>u32_</samp>’ operate on UTF-32 strings. </p> <p>For every function with prefix ‘<samp>u8_</samp>’, operating on UTF-8 strings, there is also a corresponding function with prefix ‘<samp>u16_</samp>’, operating on UTF-16 strings, and a corresponding function with prefix ‘<samp>u32_</samp>’, operating on UTF-32 strings. Their description is analogous; in this documentation we describe only the function that operates on UTF-8 strings, for brevity. </p> <p>A declaration with a variable <var>n</var> denotes the three concrete declarations with <var>n</var> = 8, <var>n</var> = 16, <var>n</var> = 32. </p> <p>All parameters starting with ‘<samp>str</samp>’ and the parameters of functions starting with <code>u8_str</code>/<code>u16_str</code>/<code>u32_str</code> denote a NUL terminated string. </p> <a name="IDX15"></a> <p>Error values are always returned through the <code>errno</code> variable, usually with a return value that indicates the presence of an error (NULL for functions that return an pointer, or -1 for functions that return an <code>int</code>). </p> <p>Functions returning a string result take a <code>(<var>resultbuf</var>, <var>lengthp</var>)</code> argument pair. If <var>resultbuf</var> is not NULL and the result fits into <code>*<var>lengthp</var></code> units, it is put in <var>resultbuf</var>, and <var>resultbuf</var> is returned. Otherwise, a freshly allocated string is returned. In both cases, <code>*<var>lengthp</var></code> is set to the length (number of units) of the returned string. In case of error, NULL is returned and <code>errno</code> is set. </p> <hr size="6"> <table cellpadding="1" cellspacing="1" border="0"> <tr><td valign="middle" align="left">[<a href="libunistring_1.html#SEC1" title="Beginning of this chapter or previous chapter"> << </a>]</td> <td valign="middle" align="left">[<a href="libunistring_3.html#SEC10" title="Next chapter"> >> </a>]</td> <td valign="middle" align="left"> </td> <td valign="middle" align="left"> </td> <td valign="middle" align="left"> </td> <td valign="middle" align="left"> </td> <td valign="middle" align="left"> </td> <td valign="middle" align="left">[<a href="libunistring.html#SEC_Top" title="Cover (top) of document">Top</a>]</td> <td valign="middle" align="left">[<a href="libunistring.html#SEC_Contents" title="Table of contents">Contents</a>]</td> <td valign="middle" align="left">[<a href="libunistring_19.html#SEC77" title="Index">Index</a>]</td> <td valign="middle" align="left">[<a href="libunistring_abt.html#SEC_About" title="About (help)"> ? </a>]</td> </tr></table> <p> <font size="-1"> This document was generated by <em>Daiki Ueno</em> on <em>July, 8 2015</em> using <a href="http://www.nongnu.org/texi2html/"><em>texi2html 1.78a</em></a>. </font> <br> </p> </body> </html>