std::basic_ios has an operator bool(). In C++11 and later
it is explicit, and only allows contextual implicit conversions.
However explicit isn't available in C++03 which causes std::istream (et al)
to have an implicit conversion to int. This can easily cause ambiguities
when calling operator<< and operator>>.
This patch uses a "bool-like" type in C++03 to work around this. The
"bool-like" type is an arbitrary pointer to member function type. It
will not convert to either int or void*, but will convert to bool.
git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@290750 91177308-0d34-0410-b5e6-96231b3b80d8
Back in r240527 I added a knob to prevent thread-unsafe functions from
being exposed. mblen(), mbtowc() and wctomb() were also added to this
list, as the latest issue of POSIX doesn't require these functions to be
thread-safe.
It turns out that the only circumstance in which these functions are not
thread-safe is in case they are used in combination with state-dependent
character sets (e.g., Shift-JIS). According to Austin Group Bug 708,
these character sets "[...] are mostly a relic of the past and which
were never supported on most POSIX systems".
Though in many cases the use of these functions can be prevented by
using the reentrant counterparts, they are the only functions that allow
you to query whether the locale's character set is state-dependent. This
means that omitting these functions removes actual functionality.
Let's be a bit less pedantic and drop the guards around these functions.
Links:
http://austingroupbugs.net/view.php?id=708http://www.open-std.org/jtc1/sc22/wg14/www/docs/n2037.htm
Reviewed by: ericwf
Differential Revision: https://reviews.llvm.org/D21436
git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@290748 91177308-0d34-0410-b5e6-96231b3b80d8
In C++03 libc++ emulates nullptr_t using a class, and #define's nullptr.
However this makes nullptr_t mangle differently between C++03 and C++11.
This breaks any function ABI which takes nullptr_t.
Thanfully Clang provides __nullptr in all dialects. This patch adds
an ABI option to switch to using __nullptr in C++03. In a perfect world
I would like to turn this on by default, since it's just ABI breaking fix
to an ABI breaking bug.
git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@290662 91177308-0d34-0410-b5e6-96231b3b80d8
This patch implements changes to allow _LIBCPP_ASSERT to throw on failure
instead of aborting. The main changes needed to do this are:
1. Change _LIBCPP_ASSERT to call a handler via a replacable function pointer
instead of calling abort directly. Additionally this patch implements two
handler functions, one which aborts and another that throws an exception.
2. Add _NOEXCEPT_DEBUG macro for disabling noexcept spec on function which
contain _LIBCPP_ASSERT. This is required in order to prevent assertion
failures throwing through a noexcept function. This macro has no effect
unless _LIBCPP_DEBUG_USE_EXCEPTIONS is defined.
Having a non-aborting _LIBCPP_ASSERT is very important to allow sane testing of
debug mode. Currently we can only have one test case per file, since the test
case will cause the program to abort. Testing debug mode this way would require
thousands of test files, most of which would be 95% boiler plate. I don't think
this is a feasible strategy. Fortunately using a throwing debug handler solves
these issues.
Additionally this patch rewrites the documentation for debug mode.
git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@290651 91177308-0d34-0410-b5e6-96231b3b80d8
It's an internal function and shouldn't be exported. It's also a source
of discrepancy in the published ABI list; these symbols aren't exported
for me on CentOS 7 or Ubuntu 16.04, leading to spurious check-cxx-abilist
failures.
Differential Revision: https://reviews.llvm.org/D27153
git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@290503 91177308-0d34-0410-b5e6-96231b3b80d8
When libcxx isn't building with an installed LLVM we copy the libcxx headers into the LLVM build directory so that a clang in that build tree can find the headers relative to itself.
This is only important in situations where you don't have headers installed under /, which is common these days on Darwin.
git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@289963 91177308-0d34-0410-b5e6-96231b3b80d8
