blocks|key|3089107|text|当使用--enable-unicode=ucs4构建时：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|3089108|>>>+import+sys
>>>+print+sys.maxunicode
1114111|code-block|syntax|javascript|3089109|当使用--enable-unicode=ucs2构建时：|3089110|>>>+import+sys
>>>+print+sys.maxunicode
65535|3089111|entityMap^0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|N|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|O|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|K|3|-4|5|6|7|Q|8|@]|9|@]|A|$]]]|L|$]]

When built with --enable-unicode=ucs4:

<pre><code>&gt;&gt;&gt; import sys
&gt;&gt;&gt; print sys.maxunicode
1114111
</code></pre>

When built with --enable-unicode=ucs2:

<pre><code>&gt;&gt;&gt; import sys
&gt;&gt;&gt; print sys.maxunicode
65535
</code></pre>

blocks|key|3089096|text|对于UCS-2为0xFFFF+(或65535)，对于UCS-4为0x10FFFF+(或1114111)：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|3089097|Py_UNICODE
PyUnicode_GetMax(void)
{
#ifdef+Py_UNICODE_WIDE
++++return+0x10FFFF;
#else
++++/*+This+is+actually+an+illegal+character,+so+it+should
+++++++not+be+passed+to+unichr.+*/
++++return+0xFFFF;
#endif
}|code-block|syntax|javascript|3089098|UCS-4模式中的最大字符数由UTF-16中可表示的最大值定义。|3089099|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|L|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|M|8|@]|9|@]|A|$]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

It's 0xFFFF (or 65535) for UCS-2, and 0x10FFFF (or 1114111) for UCS-4:

<pre><code>Py_UNICODE
PyUnicode_GetMax(void)
{
#ifdef Py_UNICODE_WIDE
 return 0x10FFFF;
#else
 /* This is actually an illegal character, so it should
 not be passed to unichr. */
 return 0xFFFF;
#endif
}
</code></pre>

The maximum character in UCS-4 mode is defined by the maxmimum value representable in UTF-16.

blocks|key|328380|text|我曾经遇到过同样的问题。我在我的wiki上记录了它，地址是|type|unstyled|depth|inlineStyleRanges|entityRanges|data|328381|http://arcoleo.org/dsawiki/Wiki.jsp?page=Python%2520UTF%2520-%2520UCS2%2520or%2520UCS4|offset|length|328382|我写了-|328383|import+sys
sys.maxunicode+>+65536+and+'UCS4'+or+'UCS2'|code-block|syntax|javascript|328384|entityMap|0|LINK|mutability|MUTABLE|url|http://arcoleo.org/dsawiki/Wiki.jsp?page=Python%2520UTF%2520-%2520UCS2%2520or%2520UCS4^0|0|0|24|0|0|0|0^^$0|@$1|2|3|4|5|6|7|U|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|V|8|@]|9|@$D|W|E|X|1|Y]]|A|$]]|$1|F|3|G|5|6|7|Z|8|@]|9|@]|A|$]]|$1|H|3|I|5|J|7|10|8|@]|9|@]|A|$K|L]]|$1|M|3|-4|5|6|7|11|8|@]|9|@]|A|$]]]|N|$O|$5|P|Q|R|A|$S|T]]]]

I had this same issue once. I documented it for myself on my wiki at

<a href="http://arcoleo.org/dsawiki/Wiki.jsp?page=Python%20UTF%20-%20UCS2%20or%20UCS4" rel="noreferrer">http://arcoleo.org/dsawiki/Wiki.jsp?page=Python%20UTF%20-%20UCS2%20or%20UCS4</a>

I wrote -

<pre><code>import sys
sys.maxunicode &gt; 65536 and 'UCS4' or 'UCS2'
</code></pre>

blocks|key|328386|text|sysconfig将从python的配置变量中获知unicode大小。|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|328387|构建标志可以像这样查询。|328388|Python2.7：|style|BOLD|328389|import+sysconfig
sysconfig.get_config_var('Py_UNICODE_SIZE')|code-block|syntax|javascript|328390|Python2.6：|328391|import+distutils
distutils.sysconfig.get_config_var('Py_UNICODE_SIZE')|328392|entityMap|0|LINK|mutability|MUTABLE|url|https://docs.python.org/2.7/library/sysconfig.html^0|0|9|0|0|0|0|A|0|0|0|A|0|0^^$0|@$1|2|3|4|5|6|7|10|8|@]|9|@$A|11|B|12|1|13]]|C|$]]|$1|D|3|E|5|6|7|14|8|@]|9|@]|C|$]]|$1|F|3|G|5|6|7|15|8|@$A|16|B|17|H|I]]|9|@]|C|$]]|$1|J|3|K|5|L|7|18|8|@]|9|@]|C|$M|N]]|$1|O|3|P|5|6|7|19|8|@$A|1A|B|1B|H|I]]|9|@]|C|$]]|$1|Q|3|R|5|L|7|1C|8|@]|9|@]|C|$M|N]]|$1|S|3|-4|5|6|7|1D|8|@]|9|@]|C|$]]]|T|$U|$5|V|W|X|C|$Y|Z]]]]

<a href="https://docs.python.org/2.7/library/sysconfig.html" rel="noreferrer">sysconfig</a> will tell the unicode size from the configuration variables of python.

The buildflags can be queried like this.

Python 2.7:

<pre><code>import sysconfig
sysconfig.get_config_var('Py_UNICODE_SIZE')
</code></pre>

Python 2.6:

<pre><code>import distutils
distutils.sysconfig.get_config_var('Py_UNICODE_SIZE')
</code></pre>

blocks|key|3089194|text|我遇到了同样的问题，并找到了一段半官方的代码，它完全可以做到这一点，而且对于有同样问题的人来说可能会很有趣：https://bitbucket.org/pypa/wheel/src/cf4e2d98ecb1f168c50a6de496959b4a10c6b122/wheel/pep425tags.py?at=default&fileviewer=file-view-default#pep425tags.py-83:89。|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|3089195|它来自will项目，该项目需要检查python是使用ucs-2还是ucs-4编译的，因为它将更改生成的二进制文件的名称。|3089196|entityMap|0|LINK|mutability|MUTABLE|url|https://bitbucket.org/pypa/wheel/src/cf4e2d98ecb1f168c50a6de496959b4a10c6b122/wheel/pep425tags.py?at=default&fileviewer=file-view-default#pep425tags.py-83:89^0|1I|4D|0|0|0^^$0|@$1|2|3|4|5|6|7|N|8|@]|9|@$A|O|B|P|1|Q]]|C|$]]|$1|D|3|E|5|6|7|R|8|@]|9|@]|C|$]]|$1|F|3|-4|5|6|7|S|8|@]|9|@]|C|$]]]|G|$H|$5|I|J|K|C|$L|M]]]]

I had the same issue and found a semi-official piece of code that does exactly that and may be interesting for people with the same issue: <a href="https://bitbucket.org/pypa/wheel/src/cf4e2d98ecb1f168c50a6de496959b4a10c6b122/wheel/pep425tags.py?at=default&amp;fileviewer=file-view-default#pep425tags.py-83:89" rel="nofollow">https://bitbucket.org/pypa/wheel/src/cf4e2d98ecb1f168c50a6de496959b4a10c6b122/wheel/pep425tags.py?at=default&amp;fileviewer=file-view-default#pep425tags.py-83:89</a>.

It comes from the wheel project which needs to check if the python is compiled with ucs-2 or ucs-4 because it will change the name of the binary file generated.

blocks|key|3302243|text|另一种方法是创建一个Unicode数组并查看itemsize：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|3302244|import+array
bytes_per_char+=+array.array('u').itemsize|code-block|syntax|javascript|3302245|引用自array+docs|offset|length|style|CODE|3302246|3302247|类型代码对应于'u'的unicode字符。在狭窄的Unicode构建上，这是2字节，在宽构建上，这是4字节。|blockquote|3302248|3302249|3302250|请注意，从Python3.3开始，窄Unicode构建和宽Unicode构建之间的区别就消失了，请参阅PEP393。array的'u'类型代码从3.3开始就被弃用，并计划在Python4.0中删除。|3302251|entityMap|0|LINK|mutability|MUTABLE|url|https://docs.python.org/2/library/array.html|1|https://www.python.org/dev/peps/pep-0393/^0|0|0|3|5|3|A|0|0|0|7|3|0|0|0|1M|5|1S|3|1F|6|1|0^^$0|@$1|2|3|4|5|6|7|14|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|15|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|16|8|@$I|17|J|18|K|L]]|9|@$I|19|J|1A|1|1B]]|A|$]]|$1|M|3|-4|5|6|7|1C|8|@]|9|@]|A|$]]|$1|N|3|O|5|P|7|1D|8|@$I|1E|J|1F|K|L]]|9|@]|A|$]]|$1|Q|3|-4|5|6|7|1G|8|@]|9|@]|A|$]]|$1|R|3|-4|5|6|7|1H|8|@]|9|@]|A|$]]|$1|S|3|T|5|6|7|1I|8|@$I|1J|J|1K|K|L]|$I|1L|J|1M|K|L]]|9|@$I|1N|J|1O|1|1P]]|A|$]]|$1|U|3|-4|5|6|7|1Q|8|@]|9|@]|A|$]]]|V|$W|$5|X|Y|Z|A|$10|11]]|12|$5|X|Y|Z|A|$10|13]]]]

Another way is to create an Unicode array and look at the itemsize:

<pre><code>import array
bytes_per_char = array.array('u').itemsize
</code></pre>

Quote from the <a href="https://docs.python.org/2/library/array.html" rel="nofollow"><code>array</code> docs</a>:

<blockquote>
 The <code>'u'</code> typecode corresponds to Python’s unicode character. On narrow Unicode builds this is 2-bytes, on wide builds this is 4-bytes.
</blockquote>

Note that the distinction between narrow and wide Unicode builds is dropped from Python 3.3 onward, see <a href="https://www.python.org/dev/peps/pep-0393/" rel="nofollow">PEP393</a>. The <code>'u'</code> typecode for <code>array</code> is deprecated since 3.3 and scheduled for removal in Python 4.0.

blocks|key|3089078|text|65535是UCS-2：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|3089079|3089080|+Thus+code+point+U%2B0000+is+encoded+as+the+number+0,+and+U%2BFFFF+is+encoded+as+65535+(which+is+FFFF16+in+hexadecimal).|blockquote|offset|length|3089081|3089082|entityMap|0|LINK|mutability|MUTABLE|url|http://en.wikipedia.org/wiki/UTF-16/UCS-2^0|0|0|1|37|0|0|0^^$0|@$1|2|3|4|5|6|7|Q|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|R|8|@]|9|@]|A|$]]|$1|C|3|D|5|E|7|S|8|@]|9|@$F|T|G|U|1|V]]|A|$]]|$1|H|3|-4|5|6|7|W|8|@]|9|@]|A|$]]|$1|I|3|-4|5|6|7|X|8|@]|9|@]|A|$]]]|J|$K|$5|L|M|N|A|$O|P]]]]

65535 is UCS-2:

<blockquote>
 <a href="http://en.wikipedia.org/wiki/UTF-16/UCS-2" rel="nofollow noreferrer">Thus code point U+0000 is encoded as the number 0, and U+FFFF is encoded as 65535 (which is FFFF16 in hexadecimal).</a>
</blockquote>

Just what the title says.

<pre><code>$ ./configure --help | grep -i ucs
 --enable-unicode[=ucs[24]]
</code></pre>

Searching the official documentation, I found this:

<blockquote>
 <a href="http://docs.python.org/3.1/library/sys.html#sys.maxunicode" rel="noreferrer">sys.maxunicode</a>: An integer giving the
 largest supported code point for a
 Unicode character. The value of this
 depends on the configuration option
 that specifies whether Unicode
 characters are stored as UCS-2 or
 UCS-4.
</blockquote>

What is not clear here is - which value(s) correspond to UCS-2 and UCS-4.

The code is expected to work on Python 2.6+.

How to find out if Python is compiled with UCS-2 or UCS-4?

Python

就像标题所说的那样。$ ./configure --help | grep -i ucs  --enable-unicode[=ucs[24]]搜索官方文档，我发现了以下内容：Unicode ：一个整数，给出了字符支持的最大码位。其Unicode值取决于指定将字符存储为UCS-2还是UCS-4的配置选项。这里不清楚的是，哪些值对应于UCS-2和UCS-4。该代码有望在Python 2.6+上运行。

问如何确定Python是使用UCS-2还是UCS-4编译的？
EN

回答 7

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问如何确定Python是使用UCS-2还是UCS-4编译的？EN

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问如何确定Python是使用UCS-2还是UCS-4编译的？
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