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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 --- - libc++ operator>>(istream&, std::string &s) not throwing exception when failbit is set and failbit exceptions enabled"
href="http://llvm.org/bugs/show_bug.cgi?id=21586">21586</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>libc++ operator>>(istream&, std::string &s) not throwing exception when failbit is set and failbit exceptions enabled
</td>
</tr>
<tr>
<th>Product</th>
<td>libc++
</td>
</tr>
<tr>
<th>Version</th>
<td>unspecified
</td>
</tr>
<tr>
<th>Hardware</th>
<td>All
</td>
</tr>
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<th>OS</th>
<td>All
</td>
</tr>
<tr>
<th>Status</th>
<td>NEW
</td>
</tr>
<tr>
<th>Severity</th>
<td>normal
</td>
</tr>
<tr>
<th>Priority</th>
<td>P
</td>
</tr>
<tr>
<th>Component</th>
<td>All Bugs
</td>
</tr>
<tr>
<th>Assignee</th>
<td>unassignedclangbugs@nondot.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>seth.cantrell@gmail.com
</td>
</tr>
<tr>
<th>CC</th>
<td>llvmbugs@cs.uiuc.edu, mclow.lists@gmail.com
</td>
</tr>
<tr>
<th>Classification</th>
<td>Unclassified
</td>
</tr></table>
<p>
<div>
<pre>I have a simple program which I believe should be throwing an exception:
// <a href="http://coliru.stacked-crooked.com/a/464c105f4ec53104">http://coliru.stacked-crooked.com/a/464c105f4ec53104</a>
#include <sstream>
#include <string>
int main() {
std::stringstream ss("");
ss.exceptions(std::ios::failbit);
std::string s;
ss >> s; // not throwing an exception under libc++
}
With libstdc++ and VC++'s this program does indeed throw an exception. However
with libc++ it does not. Interestingly a direct check of the streams failbit
shows that libc++'s implementation is setting the failbit, as are the other
implementations, but for some reason this does not cause an exception to be
thrown when the streaming operator fails.
// <a href="http://coliru.stacked-crooked.com/a/e4a649ee145b0475">http://coliru.stacked-crooked.com/a/e4a649ee145b0475</a>
#include <sstream>
#include <string>
#include <iostream>
int main() {
std::stringstream ss("");
std::string s;
ss >> s;
std::cout << ss.fail() << '\n'; // prints '1' for all tested
implementations
}
If failbit exceptions are enabled after the bit is set, the .exceptions()
member function throws as expected:
// <a href="http://coliru.stacked-crooked.com/a/601cb5d7c5c2b156">http://coliru.stacked-crooked.com/a/601cb5d7c5c2b156</a>
#include <sstream>
#include <string>
int main() {
std::stringstream ss("");
std::string s;
ss >> s;
ss.exceptions(std::ios::failbit); // throws on all tested
implementations
}
I don't know what version of libc++ is being used on
coliru.stacked-crooked.com, but I'm also reproducing this issue with r222085 /
9a1468f79ea23f14a258af094af06993fe72e3a9</pre>
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