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From: "wjl at icecavern dot net" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug c++/59873] New: The value of char32_t U'\u0000' and char16_t u'\u000' is 1, instead of 0. Date: Sat, 18 Jan 2014 22:02:00 -0000 [thread overview] Message-ID: <bug-59873-4@http.gcc.gnu.org/bugzilla/> (raw) http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59873 Bug ID: 59873 Summary: The value of char32_t U'\u0000' and char16_t u'\u000' is 1, instead of 0. Product: gcc Version: 4.8.3 Status: UNCONFIRMED Severity: major Priority: P3 Component: c++ Assignee: unassigned at gcc dot gnu.org Reporter: wjl at icecavern dot net I found a major bug with char32_t and char16_t literals when trying to encode a U+0000 (Null). The following expressions have the numeric value 1, instead of the correct value, 0. This makes it impossible to use code which has these literals. The following typescript shows a program that demonstrates the problem, and shows the behavior of g++ (incorrect) vs. clang++ (correct): $ cat test.c++ #include <cstdint> #include <iostream> int main() { char32_t null = U'\u0000'; std::cerr << "null (char32_t) = " << null << '\n'; std::cerr << "null (uint32_t) = " << uint32_t(null) << '\n'; char32_t soh = U'\u0001'; std::cerr << "soh (char32_t) = " << soh << '\n'; std::cerr << "soh (uint32_t) = " << uint32_t(soh) << '\n'; std::cerr << "char32_t null == soh = " << (U'\u0000' == U'\u0001') << '\n'; char16_t null16 = u'\u0000'; std::cerr << "null (char16_t) = " << null16 << '\n'; std::cerr << "null (uint16_t) = " << uint16_t(null16) << '\n'; char16_t soh16 = u'\u0001'; std::cerr << "soh (char16_t) = " << soh16 << '\n'; std::cerr << "soh (uint16_t) = " << uint16_t(soh16) << '\n'; std::cerr << "char16_t null == soh = " << (u'\u0000' == u'\u0001') << '\n'; } $ g++ --version g++ (Debian 4.8.2-10) 4.8.2 Copyright (C) 2013 Free Software Foundation, Inc. This is free software; see the source for copying conditions. There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. $ g++ -Wall -Wextra -std=c++11 test.c++ $ ./a.out null (char32_t) = 1 null (uint32_t) = 1 soh (char32_t) = 1 soh (uint32_t) = 1 char32_t null == soh = 1 null (char16_t) = 1 null (uint16_t) = 1 soh (char16_t) = 1 soh (uint16_t) = 1 char16_t null == soh = 1 $ clang++ --version Debian clang version 3.5-1 (trunk) (based on LLVM 3.5) Target: x86_64-pc-linux-gnu Thread model: posix $ clang++ -Wall -Wextra -std=c++11 test.c++ $ ./a.out null (char32_t) = 0 null (uint32_t) = 0 soh (char32_t) = 1 soh (uint32_t) = 1 char32_t null == soh = 0 null (char16_t) = 0 null (uint16_t) = 0 soh (char16_t) = 1 soh (uint16_t) = 1 char16_t null == soh = 0
next reply other threads:[~2014-01-18 22:02 UTC|newest] Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top 2014-01-18 22:02 wjl at icecavern dot net [this message] 2014-01-18 22:05 ` [Bug c++/59873] " wjl at icecavern dot net 2014-01-18 22:10 ` wjl at icecavern dot net 2014-01-18 23:19 ` wjl at icecavern dot net 2014-01-18 23:21 ` glisse at gcc dot gnu.org 2014-01-18 23:33 ` wjl at icecavern dot net 2014-01-18 23:40 ` schwab@linux-m68k.org 2014-01-18 23:47 ` wjl at icecavern dot net 2014-01-20 0:16 ` wjl at icecavern dot net 2014-01-20 0:19 ` wjl at icecavern dot net 2014-07-20 20:51 ` [Bug c++/59873] The value of char32_t U'\u0000' and char16_t u'\u0000' " richard-gccbugzilla at metafoo dot co.uk 2015-04-30 10:37 ` paolo.carlini at oracle dot com
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