[PATCH] libc++: Make support for thread-unsafe C functions optional

[Ed Schouten]

Hi jroelofs, mclow.lists,

One of the aspects of CloudABI is that it aims to help you write code that is thread-safe out of the box. This is very important if you want to write libraries that are easy to reuse. For CloudABI we decided to not provide the thread-unsafe functions. So far this is working out pretty well, as thread-unsafety issues are detected really early on.

The following patch adds a knob to libc++, _LIBCPP_HAS_NO_THREAD_UNSAFE_C_FUNCTIONS, that can be set to disable thread-unsafe functions that can easily be avoided in practice. The following functions are not thread-safe:

  - `<clocale>`: locale handles should be preferred over `setlocale()`.
  - `<cstdlib>`: `mbrlen()`, `mbrtowc()` and `wcrtomb()` should be preferred over their non-restartable counterparts.
  - `<ctime>`: `asctime()`, `ctime()`, `gmtime()` and `localtime()` are not thread-safe. The first two are also deprecated by POSIX.

REPOSITORY
  rL LLVM

http://reviews.llvm.org/D8703

Files:
  CMakeLists.txt
  include/__config
  include/clocale
  include/cstdlib
  include/cstring
  include/ctime
  src/locale.cpp
  test/CMakeLists.txt
  test/libcxx/test/config.py
  test/lit.site.cfg.in
  test/std/depr/depr.c.headers/stdlib_h.pass.cpp
  test/std/depr/depr.c.headers/string_h.pass.cpp
  test/std/language.support/support.runtime/cstdlib.pass.cpp
  test/std/language.support/support.runtime/ctime.pass.cpp
  test/std/localization/c.locales/clocale.pass.cpp
  test/std/strings/c.strings/cstring.pass.cpp
  test/std/utilities/date.time/no.thread.unsafe.c.functions/asctime.fail.cpp
  test/std/utilities/date.time/no.thread.unsafe.c.functions/ctime.fail.cpp
  test/std/utilities/date.time/no.thread.unsafe.c.functions/gmtime.fail.cpp
  test/std/utilities/date.time/no.thread.unsafe.c.functions/lit.local.cfg
  test/std/utilities/date.time/no.thread.unsafe.c.functions/localtime.fail.cpp
  test/std/utilities/date.time/tested_elsewhere.pass.cpp

EMAIL PREFERENCES
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