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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW --- - libc++ should have its own classic_table"
href="http://llvm.org/bugs/show_bug.cgi?id=21506">21506</a>
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<th>Summary</th>
<td>libc++ should have its own classic_table
</td>
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<th>Product</th>
<td>libc++
</td>
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<th>Version</th>
<td>unspecified
</td>
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<th>Hardware</th>
<td>PC
</td>
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<th>OS</th>
<td>Linux
</td>
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<th>Status</th>
<td>NEW
</td>
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<th>Severity</th>
<td>normal
</td>
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<th>Priority</th>
<td>P
</td>
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<th>Component</th>
<td>All Bugs
</td>
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<th>Assignee</th>
<td>danalbert@google.com
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<th>Reporter</th>
<td>danalbert@google.com
</td>
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<th>CC</th>
<td>eric@efcs.ca, jonathan@codesourcery.com, llvmbugs@cs.uiuc.edu, mclow.lists@gmail.com
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<th>Classification</th>
<td>Unclassified
</td>
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<p>
<div>
<pre>We should probably be shipping our own classic_table instead of relying on one
from the underlying C library.
1. The C library isn't required to even provide such a table. IIRC, musl does
not.
2. The underlying type of the table is undefined, as are the values that map to
each mask. This is responsible for the #ifdef hell stew in [1].
3. Some C libraries (bionic, openbsd, and newlib, possibly others) use an 8-bit
mask for the table. It's still not 100% clear if this is okay, or if we need to
be able to define more than 8 values such that for any two values a and b, a &
b == 0. There are known failures in some libc++ tests [2] caused by this.
Defining our own table with a mask that is at least 16-bits wide (possibly 32)
would get us out of this mess.
I'll upload a patch soonish (once I find time) that does this unless anyone has
good reasons not to take this approach.
[1]: <a href="https://github.com/llvm-mirror/libcxx/blob/master/include/__locale#L324">https://github.com/llvm-mirror/libcxx/blob/master/include/__locale#L324</a>
[2]:
localization/locale.categories/category.ctype/locale.ctype.byname/is_1.pass.cpp
localization/locale.categories/category.ctype/locale.ctype.byname/scan_is.pass.cpp</pre>
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