Roman Lebedev c65d39a464 [libc++] Add _LIBCPP_ENABLE_NODISCARD and _LIBCPP_NODISCARD_EXT to allow pre-C++2a [[nodiscard]] ... Summary: The `[[nodiscard]]` attribute is intended to help users find bugs where function return values are ignored when they shouldn't be. After C++17 the C++ standard has started to declared such library functions as `[[nodiscard]]`. However, this application is limited and applies only to dialects after C++17. Users who want help diagnosing misuses of STL functions may desire a more liberal application of `[[nodiscard]]`. For this reason libc++ provides an extension that does just that! The extension must be enabled by defining `_LIBCPP_ENABLE_NODISCARD`. The extended applications of `[[nodiscard]]` takes two forms: 1. Backporting `[[nodiscard]]` to entities declared as such by the standard in newer dialects, but not in the present one. 2. Extended applications of `[[nodiscard]]`, at the libraries discretion, applied to entities never declared as such by the standard. Users may also opt-out of additional applications `[[nodiscard]]` using additional macros. Applications of the first form, which backport `[[nodiscard]]` from a newer dialect may be disabled using macros specific to the dialect it was added. For example `_LIBCPP_DISABLE_NODISCARD_AFTER_CXX17`. Applications of the second form, which are pure extensions, may be disabled by defining `_LIBCPP_DISABLE_NODISCARD_EXT`. This patch was originally written by me (Roman Lebedev), then but then reworked by Eric Fiselier. Reviewers: mclow.lists, thakis, EricWF Reviewed By: thakis, EricWF Subscribers: llvm-commits, mclow.lists, lebedev.ri, EricWF, rjmccall, Quuxplusone, cfe-commits, christof Differential Revision: https://reviews.llvm.org/D45179 llvm-svn: 342808		2018-09-22 17:54:48 +00:00
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google-benchmark	Remove BUILD file from google-benchmark	2018-07-10 13:25:26 +00:00
libcxx	[libc++] Add _LIBCPP_ENABLE_NODISCARD and _LIBCPP_NODISCARD_EXT to allow pre-C++2a [[nodiscard]]	2018-09-22 17:54:48 +00:00
symcheck-blacklists	Start libc++ python cleanup and consolidation.	2017-02-09 22:53:14 +00:00
cat_files.py	Fix creating __generated_config on Windows	2017-01-03 03:55:29 +00:00
gen_link_script.py	Start libc++ python cleanup and consolidation.	2017-02-09 22:53:14 +00:00
merge_archives.py	Use CMAKE_AR instead of the system default 'ar' for merging static libraries	2017-09-13 06:55:44 +00:00
not.py	Start libc++ python cleanup and consolidation.	2017-02-09 22:53:14 +00:00
sym_diff.py	Start libc++ python cleanup and consolidation.	2017-02-09 22:53:14 +00:00
sym_extract.py	Start libc++ python cleanup and consolidation.	2017-02-09 22:53:14 +00:00
sym_match.py	Start libc++ python cleanup and consolidation.	2017-02-09 22:53:14 +00:00