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| author | Arthur O'Dwyer <arthur.j.odwyer@gmail.com> | 2021-08-06 14:50:09 -0400 |
|---|---|---|
| committer | Arthur O'Dwyer <arthur.j.odwyer@gmail.com> | 2021-08-11 13:40:31 -0400 |
| commit | c85a094bcaad233b1a7f029d29f37cfa70ef10c6 (patch) | |
| tree | 76eaf6e56c86b95c920778d9f1887f63052167fe /libcxx | |
| parent | 6789c4564a4b33049cb1335d9b8078057af2dc11 (diff) | |
| download | llvm-c85a094bcaad233b1a7f029d29f37cfa70ef10c6.zip llvm-c85a094bcaad233b1a7f029d29f37cfa70ef10c6.tar.gz llvm-c85a094bcaad233b1a7f029d29f37cfa70ef10c6.tar.bz2 | |
[libc++] Restore `basic_ios`'s implicit conversion to `bool` in C++03 mode.
efriedma noted that D104682 broke this test case, reduced from SPEC2006.
#include <istream>
bool a(std::istream a) {
return a.getline(0,0) == 0;
}
We can unbreak it by restoring the conversion to something-convertible-to-bool.
We chose `void*` in order to match libstdc++.
For more ancient history, see PR19460: https://bugs.llvm.org/show_bug.cgi?id=19460
Differential Revision: https://reviews.llvm.org/D107663
(cherry picked from commit c1a8f12873783e8f4827437f6b2dddadfc58109d)
Diffstat (limited to 'libcxx')
| -rw-r--r-- | libcxx/include/ios | 7 | ||||
| -rw-r--r-- | libcxx/test/std/input.output/iostreams.base/ios/iostate.flags/bool.pass.cpp | 10 |
2 files changed, 15 insertions, 2 deletions
diff --git a/libcxx/include/ios b/libcxx/include/ios index 3128bca..c9230d6 100644 --- a/libcxx/include/ios +++ b/libcxx/include/ios @@ -607,8 +607,15 @@ public: static_assert((is_same<_CharT, typename traits_type::char_type>::value), "traits_type::char_type must be the same type as CharT"); +#ifdef _LIBCPP_CXX03_LANG + // Preserve the ability to compare with literal 0, + // and implicitly convert to bool, but not implicitly convert to int. + _LIBCPP_INLINE_VISIBILITY + operator void*() const {return fail() ? nullptr : (void*)this;} +#else _LIBCPP_INLINE_VISIBILITY explicit operator bool() const {return !fail();} +#endif _LIBCPP_INLINE_VISIBILITY bool operator!() const {return fail();} _LIBCPP_INLINE_VISIBILITY iostate rdstate() const {return ios_base::rdstate();} diff --git a/libcxx/test/std/input.output/iostreams.base/ios/iostate.flags/bool.pass.cpp b/libcxx/test/std/input.output/iostreams.base/ios/iostate.flags/bool.pass.cpp index 59896c8..3fe50c6 100644 --- a/libcxx/test/std/input.output/iostreams.base/ios/iostate.flags/bool.pass.cpp +++ b/libcxx/test/std/input.output/iostreams.base/ios/iostate.flags/bool.pass.cpp @@ -24,10 +24,16 @@ int main(int, char**) assert(static_cast<bool>(ios) == !ios.fail()); ios.setstate(std::ios::failbit); assert(static_cast<bool>(ios) == !ios.fail()); - static_assert((!std::is_convertible<std::ios, void*>::value), ""); static_assert((!std::is_convertible<std::ios, int>::value), ""); static_assert((!std::is_convertible<std::ios const&, int>::value), ""); - static_assert((!std::is_convertible<std::ios, bool>::value), ""); +#if TEST_STD_VER >= 11 + static_assert(!std::is_convertible<std::ios, void*>::value, ""); + static_assert(!std::is_convertible<std::ios, bool>::value, ""); +#else + static_assert(std::is_convertible<std::ios, void*>::value, ""); + static_assert(std::is_convertible<std::ios, bool>::value, ""); + (void)(ios == 0); // SPEC2006 apparently relies on this to compile +#endif return 0; } |