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From: "alex-j-a at hotmail dot co.uk" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug libstdc++/64814] New: std::copy_n advances InputIterator one *less* time than necessary. Date: Tue, 27 Jan 2015 03:49:00 -0000 [thread overview] Message-ID: <bug-64814-4@http.gcc.gnu.org/bugzilla/> (raw) https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64814 Bug ID: 64814 Summary: std::copy_n advances InputIterator one *less* time than necessary. Product: gcc Version: 4.9.2 Status: UNCONFIRMED Severity: major Priority: P3 Component: libstdc++ Assignee: unassigned at gcc dot gnu.org Reporter: alex-j-a at hotmail dot co.uk Bug 50119 is related. The issue should be clear from the example below; I've confirmed the output on several web-based compilers (I'm using a chromebook in standard config) all of which claim to use GCC. minimal failing example: #include <iostream> #include <sstream> #include <algorithm> #include <iterator> #include <string> int main() { std::istringstream ss("123456789012"); std::string output; auto readIter = std::istreambuf_iterator<char>(ss); for (int i = 0; i < 3; ++i) { output.clear(); auto inserter = std::back_inserter(output); // Works - outputs 123456789012 //for (int j = 0; j < 4; ++j) // *inserter++ = *readIter++; // Doesn't work - outputs 123445677890 std::copy_n(readIter, 4, inserter); std::cout << output; } } The following works perfectly as a drop-in replacement from my tests: template <typename InputIt, typename SizeT, typename OutputIt> OutputIt copy_n(InputIt first, SizeT count, OutputIt result) { for (; count > 0; --count) *result++ = *first++; return result; }
next reply other threads:[~2015-01-27 3:49 UTC|newest] Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top 2015-01-27 3:49 alex-j-a at hotmail dot co.uk [this message] 2015-01-27 11:28 ` [Bug libstdc++/64814] " redi at gcc dot gnu.org 2015-01-27 16:06 ` redi at gcc dot gnu.org 2015-01-27 16:09 ` alex-j-a at hotmail dot co.uk 2015-01-27 16:18 ` redi at gcc dot gnu.org 2015-01-27 16:29 ` redi at gcc dot gnu.org 2015-01-27 16:40 ` alex-j-a at hotmail dot co.uk 2015-01-27 16:51 ` alex-j-a at hotmail dot co.uk 2015-01-27 17:06 ` redi at gcc dot gnu.org 2015-01-28 13:40 ` redi at gcc dot gnu.org 2015-01-29 21:06 ` alex-j-a at hotmail dot co.uk
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