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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW --- - in -traditional mode, the preprocessor should only process directives whose '#' appears in column 1"
href="https://llvm.org/bugs/show_bug.cgi?id=31886">31886</a>
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<th>Summary</th>
<td>in -traditional mode, the preprocessor should only process directives whose '#' appears in column 1
</td>
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<th>Product</th>
<td>clang
</td>
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<th>Version</th>
<td>unspecified
</td>
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<th>Hardware</th>
<td>All
</td>
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<th>OS</th>
<td>All
</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
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<th>Component</th>
<td>-New Bugs
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<th>Assignee</th>
<td>unassignedclangbugs@nondot.org
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<th>Reporter</th>
<td>froydnj@gmail.com
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<th>CC</th>
<td>llvm-bugs@lists.llvm.org
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<th>Classification</th>
<td>Unclassified
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<p>
<div>
<pre>Relaying this bug report on behalf of Zack Weinberg:
In -traditional mode, the preprocessor should only process directives
whose '#' appears in column 1. For instance, in this fragment ...
#ifndef foo
#ifdef bar
quux
#endif
#endif
... no tokens survive preprocessing in the standard mode, but the
expected output of 'cc -E -traditional' (ignoring blank lines and line
number annotations) is
#ifdef bar
quux
#endif
clang, however, has a bug in which the nested #endif is *not* ignored,
causing the subsequent non-nested #endif to trigger an error:
#ifdef bar
quux
test.c:5:2: error: #endif without #if
#endif
^
1 error generated.
This may not just affect #endif: clang preprocesses *this* fragment ...
/* this comment is not indented */
#ifdef bar
quux
#else
greeble
#endif
... to just 'greeble' and no errors, with or without -traditional.
I observe this behavior with both
'clang version 3.8.1-17 (tags/RELEASE_381/final)' and
'clang version 3.9.1-4 (tags/RELEASE_391/rc2)' as supplied by Debian.
Another person has reported identical behavior with
'Apple LLVM version 8.0.0 (clang-800.0.42.1)'.</pre>
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