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<H1><A NAME="SECTION0001100000000000000000">
10 PEP 331: Locale-Independent Float/String Conversions</A>
</H1>

<P>
The <tt class="module">locale</tt> modules lets Python software select various
conversions and display conventions that are localized to a particular
country or language.  However, the module was careful to not change
the numeric locale because various functions in Python's
implementation required that the numeric locale remain set to the
<code>'C'</code> locale.  Often this was because the code was using the C library's
<tt class="cfunction">atof()</tt> function.  

<P>
Not setting the numeric locale caused trouble for extensions that used
third-party C libraries, however, because they wouldn't have the
correct locale set.  The motivating example was GTK+, whose user
interface widgets weren't displaying numbers in the current locale.

<P>
The solution described in the PEP is to add three new functions to the
Python API that perform ASCII-only conversions, ignoring the locale
setting:

<P>

<UL>
<LI><tt class="cfunction">PyOS_ascii_strtod(<var>str</var>, <var>ptr</var>)</tt> 
and <tt class="cfunction">PyOS_ascii_atof(<var>str</var>, <var>ptr</var>)</tt> 
both convert a string to a C <tt class="ctype">double</tt>.
</LI>
<LI><tt class="cfunction">PyOS_ascii_formatd(<var>buffer</var>, <var>buf_len</var>, <var>format</var>, <var>d</var>)</tt> converts a <tt class="ctype">double</tt> to an ASCII string.
</LI>
</UL>

<P>
The code for these functions came from the GLib library
(<a class="url" href="http://developer.gnome.org/arch/gtk/glib.html">http://developer.gnome.org/arch/gtk/glib.html</a>), whose
developers kindly relicensed the relevant functions and donated them
to the Python Software Foundation.  The <tt class="module">locale</tt> module 
can now change the numeric locale, letting extensions such as GTK+ 
produce the correct results.

<P>
<div class="seealso">
  <p class="heading">See Also:</p>

<dl compact="compact" class="seerfc">
    <dt><a href="http://www.python.org/peps/pep-0331.html"
        title="Locale-Independent Float/String Conversions"
        >PEP 331, <em>Locale-Independent Float/String Conversions</em></a>
    <dd>Written by Christian R. Reis, and implemented by Gustavo Carneiro.
  </dl>
</div>      

<P>

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	52
	53	<H1><A NAME="SECTION0001100000000000000000">
	54	10 PEP 331: Locale-Independent Float/String Conversions</A>
	55	</H1>
	56
	57	<P>
	58	The <tt class="module">locale</tt> modules lets Python software select various
	59	conversions and display conventions that are localized to a particular
	60	country or language. However, the module was careful to not change
	61	the numeric locale because various functions in Python's
	62	implementation required that the numeric locale remain set to the
	63	<code>'C'</code> locale. Often this was because the code was using the C library's
	64	<tt class="cfunction">atof()</tt> function.
65
66	<P>
67	Not setting the numeric locale caused trouble for extensions that used
68	third-party C libraries, however, because they wouldn't have the
69	correct locale set. The motivating example was GTK+, whose user
70	interface widgets weren't displaying numbers in the current locale.
71
72	<P>
73	The solution described in the PEP is to add three new functions to the
74	Python API that perform ASCII-only conversions, ignoring the locale
75	setting:
76
77	<P>
78
79	<UL>
80	<LI><tt class="cfunction">PyOS_ascii_strtod(<var>str</var>, <var>ptr</var>)</tt>
81	and <tt class="cfunction">PyOS_ascii_atof(<var>str</var>, <var>ptr</var>)</tt>
82	both convert a string to a C <tt class="ctype">double</tt>.
83	</LI>
84	<LI><tt class="cfunction">PyOS_ascii_formatd(<var>buffer</var>, <var>buf_len</var>, <var>format</var>, <var>d</var>)</tt> converts a <tt class="ctype">double</tt> to an ASCII string.
85	</LI>
86	</UL>
87
88	<P>
89	The code for these functions came from the GLib library
90	(<a class="url" href="http://developer.gnome.org/arch/gtk/glib.html">http://developer.gnome.org/arch/gtk/glib.html</a>), whose
91	developers kindly relicensed the relevant functions and donated them
92	to the Python Software Foundation. The <tt class="module">locale</tt> module
93	can now change the numeric locale, letting extensions such as GTK+
94	produce the correct results.
95
96	<P>
97	<div class="seealso">
98	<p class="heading">See Also:</p>
99
100	<dl compact="compact" class="seerfc">
101	<dt><a href="http://www.python.org/peps/pep-0331.html"
102	title="Locale-Independent Float/String Conversions"
103	>PEP 331, <em>Locale-Independent Float/String Conversions</em></a>
104	<dd>Written by Christian R. Reis, and implemented by Gustavo Carneiro.
105	</dl>
106	</div>
107
108	<P>
109
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