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<h1 class="chapter"> <a href="libunistring_toc.html#TOC55">9. Display width <code><uniwidth.h></code></a> </h1>
<p>This include file declares functions that return the display width, measured
in columns, of characters or strings, when output to a device that uses
non-proportional fonts.
</p>
<a name="IDX779"></a>
<p>Note that for some rarely used characters the actual fonts or terminal
emulators can use a different width. There is no mechanism for communicating
the display width of characters across a Unix pseudo-terminal (tty). Also,
there are scripts with complex rendering, like the Indic scripts. For these
scripts, there is no such concept as non-proportional fonts. Therefore
the results of these functions usually work fine on most scripts and on
most characters but can fail to represent the actual display width.
</p>
<p>These functions are locale dependent. The <var>encoding</var> argument identifies
the encoding (e.g. <code>"ISO-8859-2"</code> for Polish).
</p>
<a name="IDX780"></a>
<a name="IDX781"></a>
<a name="IDX782"></a>
<dl>
<dt><u>Function:</u> int <b>uc_width</b><i> (ucs4_t <var>uc</var>, const char *<var>encoding</var>)</i>
<a name="IDX783"></a>
</dt>
<dd><p>Determines and returns the number of column positions required for <var>uc</var>.
Returns -1 if <var>uc</var> is a control character that has an influence on the
column position when output.
</p></dd></dl>
<dl>
<dt><u>Function:</u> int <b>u8_width</b><i> (const uint8_t *<var>s</var>, size_t <var>n</var>, const char *<var>encoding</var>)</i>
<a name="IDX784"></a>
</dt>
<dt><u>Function:</u> int <b>u16_width</b><i> (const uint16_t *<var>s</var>, size_t <var>n</var>, const char *<var>encoding</var>)</i>
<a name="IDX785"></a>
</dt>
<dt><u>Function:</u> int <b>u32_width</b><i> (const uint32_t *<var>s</var>, size_t <var>n</var>, const char *<var>encoding</var>)</i>
<a name="IDX786"></a>
</dt>
<dd><p>Determines and returns the number of column positions required for first
<var>n</var> units (or fewer if <var>s</var> ends before this) in <var>s</var>. This
function ignores control characters in the string.
</p></dd></dl>
<dl>
<dt><u>Function:</u> int <b>u8_strwidth</b><i> (const uint8_t *<var>s</var>, const char *<var>encoding</var>)</i>
<a name="IDX787"></a>
</dt>
<dt><u>Function:</u> int <b>u16_strwidth</b><i> (const uint16_t *<var>s</var>, const char *<var>encoding</var>)</i>
<a name="IDX788"></a>
</dt>
<dt><u>Function:</u> int <b>u32_strwidth</b><i> (const uint32_t *<var>s</var>, const char *<var>encoding</var>)</i>
<a name="IDX789"></a>
</dt>
<dd><p>Determines and returns the number of column positions required for <var>s</var>.
This function ignores control characters in the string.
</p></dd></dl>
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