Libc++ is used as a system library on macOS and iOS (amongst others). In order
for users to be able to compile a binary that is intended to be deployed to an
older version of the platform, clang provides the
availability attribute <https://clang.llvm.org/docs/AttributeReference.html#availability>_
that can be placed on declarations to describe the lifecycle of a symbol in the
library.
See docs/DesignDocs/AvailabilityMarkup.rst for more information.
Differential Revision: https://reviews.llvm.org/D31739
llvm-svn: 302172
Summary:
system_error::message() uses `strerror` for the generic and system categories. This function is not thread safe.
The fix is to use `strerror_r`. It has been available since 2001 for GNU libc and since BSD 4.4 on FreeBSD/OS X.
On platforms with GNU libc the extended version is used which always returns a valid string, even if an error occurs.
In single-threaded builds `strerror` is still used.
See https://llvm.org/bugs/show_bug.cgi?id=25598
Reviewers: majnemer, mclow.lists
Subscribers: erik65536, cfe-commits, emaste
Differential Revision: http://reviews.llvm.org/D20903
llvm-svn: 272633
Brian Cain