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<base href="http://llvm.org/bugs/" />
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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW --- - ctype do_is doesn't work when ctype_base::mask isn't a proper bitmask"
href="http://llvm.org/bugs/show_bug.cgi?id=22858">22858</a>
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<th>Summary</th>
<td>ctype do_is doesn't work when ctype_base::mask isn't a proper bitmask
</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>All
</td>
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<th>Status</th>
<td>NEW
</td>
</tr>
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<th>Severity</th>
<td>normal
</td>
</tr>
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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>unassignedclangbugs@nondot.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>jonathan@codesourcery.com
</td>
</tr>
<tr>
<th>CC</th>
<td>llvmbugs@cs.uiuc.edu, mclow.lists@gmail.com
</td>
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<th>Classification</th>
<td>Unclassified
</td>
</tr></table>
<p>
<div>
<pre>This testcase demonstrates the issue on Newlib systems:
#include <locale>
#include <assert.h>
class CheckUpper : public std::ctype_byname<wchar_t> {
public:
CheckUpper() : std::ctype_byname<wchar_t>("C",0) { }
void check() {
assert(false == do_is(ctype_base::upper, (L"a")[0]));
}
};
int main() {
CheckUpper().check();
}
The mask for alpha/upper/lower is defined as this in the Newlib section of the
ctype_base mask definitions in `<__locale>`:
static const mask upper = _U;
static const mask lower = _L;
static const mask alpha = _U | _L;
Here's the definition of `do_is` in src/locale.cpp:
1260 bool
1261 ctype_byname<wchar_t>::do_is(mask m, char_type c) const
1262 {
1263 #ifdef _LIBCPP_WCTYPE_IS_MASK
1264 return static_cast<bool>(iswctype_l(c, m, __l));
1265 #else
1266 bool result = false;
1267 wint_t ch = static_cast<wint_t>(c);
1268 if (m & space) result |= (iswspace_l(ch, __l) != 0);
1269 if (m & print) result |= (iswprint_l(ch, __l) != 0);
1270 if (m & cntrl) result |= (iswcntrl_l(ch, __l) != 0);
1271 if (m & upper) result |= (iswupper_l(ch, __l) != 0);
1272 if (m & lower) result |= (iswlower_l(ch, __l) != 0);
1273 if (m & alpha) result |= (iswalpha_l(ch, __l) != 0);
1274 if (m & digit) result |= (iswdigit_l(ch, __l) != 0);
1275 if (m & punct) result |= (iswpunct_l(ch, __l) != 0);
1276 if (m & xdigit) result |= (iswxdigit_l(ch, __l) != 0);
1277 if (m & blank) result |= (iswblank_l(ch, __l) != 0);
1278 return result;
1279 #endif
1280 }
In this example, line `1273` sets the result to true, but lower_a is not an
upper-case character, so ยง 22.3.3.1.1 doesn't hold true for isupper:
<span class="quote">> ...
> template <class charT> bool isupper (charT c, const locale& loc);
> template <class charT> bool islower (charT c, const locale& loc);
> template <class charT> bool isalpha (charT c, const locale& loc);
> ...
> 1 Each of these functions isF returns the result of the expression:
> `use_facet< ctype<charT> >(loc).is(ctype_base::F, c)`
> where F is the ctype_base::mask value corresponding to that function (22.4.1)</span >
A few months ago, I put in a patch that changes all of the lines like `if (m &
alpha) ...` to `if ((m & alpha) == alpha)` to avoid this problem, and shortly
thereafter reverted the patch thinking that it was non-conforming. Now I'm not
so sure I should have reverted it.</pre>
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