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|
# Platform and library support for Trompeloeil
<!-- no toc -->
- [Using libc\+\+ with Trompeloeil](#using_libcxx)
- [Using sanitizers with Trompeloeil](#using_sanitizers)
- [Compiler versions in sample Linux distributions](#compilers_in_distributions)
- [Ubuntu](#compilers_in_ubuntu)
- [In summary](#ubuntu_summary)
- [In detail](#ubuntu_detail)
- [Fedora](#compilers_in_fedora)
- [Tested configurations](#tested_configurations)
- [Testing Trompeloeil on Artful Aardvark (Ubuntu 17.10)](#testing_on_artful)
- [`std::to_string()` is not defined for some versions of `libstdc++-v3`](#defect_to_string)
- [Glibc 2.26 no longer supplies `xlocale.h`](#defect_xlocale)
- [Glibc 2.26 `std::signbit()` broken for GCC compilers < 6](#defect_signbit)
- [Conclusion](#artful_conclusion)
- [Supporting incomplete standard libraries](#incomplete_stdlib)
- [Replacing `std::recursive_mutex`](#custom_recursive_mutex)
- [Replacing `std::atomic<T>`](#custom_std_atomic)
- [Replacing `std::unique_lock<T>`](#custom_std_unique_lock)
## <A name="using_libcxx"/> Using libc\+\+ with Trompeloeil
On some distributions `clang` is configured to use `libstdc++-v3` as the
implementation of the C\+\+ Standard Library. In order to use `libc++`,
pass the `-stdlib=libc++` command line flag to the compiler.
For example,
```text
clang++-5.0 -std=c++14 -stdlib=libc++ <other command line arguments>
```
To use `libc++` with `g++` a few more command line flags need to be passed.
This is a command line known to work with `g++-6`,
```text
g++-6 -std=c++14 -nostdinc++ -isystem/usr/include/c++/v1 \
<other command line arguments> \
-nodefaultlibs -lc++ -lc++abi -lm -lc -lgcc_s -lgcc
```
## <A name="using_sanitizers"/> Using sanitizers with Trompeloeil
Trompeloeil test cases have been compiled and run without error with
AddressSanitizer (ASan), Undefined Behavior Sanitizer (UBSan) and
Thread Sanitizer (TSan).
Feel free to add `-fsanitize=address`, `-fsanitize=thread` or
`-fsanitize=undefined` to your compiler command lines, especially
when unit testing.
Maybe your compiler supports `-fsanitize-address-use-after-scope`.
Add that flag as well.
## <A name="compilers_in_distributions"/> Compiler versions in sample Linux distributions
### <A name="compilers_in_ubuntu"/> Ubuntu
Canonical supports the `main` component of the repositories of a release.
Canonical does not support the `universe` component. Support for `universe`
is provided by the Ubuntu community. If a compiler or library is in `universe`
for a particular release, then there is no guarantee that there will be a
release of that compiler or library in the next or any future release of
Ubuntu, let alone updates in the current release.
Either migrate compilers and libraries with each Ubuntu release or take
control of your toolchain and remove a dependency on the platform. In the
latter case you then have the option of supporting the Ubuntu community
with a contribution of your toolchain to `universe`.
For more information, see
ubuntu.com, "Repositories" \
Available: <https://help.ubuntu.com/community/Repositories> \
Accessed: 29 October 2017
#### <A name="ubuntu_summary"/> In summary
```text
Trusty Tahr Xenial Xerus Zesty Zapus Artful Aardvark Bionic Beaver
(14.04LTS) (16.04LTS) (17.04) (17.10) (18.04LTS)
Released 2014-04-17 2016-04-21 2017-04-17 2017-10-19 2018-04
Supported to 2019-04 2021-04 2018-01 2018-07 2023-04
Compiler(s) g++-4.8.4 g++-5 g++-6 g++-7 TODO
clang++-3.5 clang++-4.0 clang++-4.0 universe TODO
clang++-5.0 TODO
libc++-dev universe universe universe universe TODO
1.0~svn199600-1 3.7.0 3.9.1 3.9.1 TODO
```
#### <A name="ubuntu_detail"/> In detail
```text
Trusty Tahr Xenial Xerus Zesty Zapus Artful Aardvark Bionic Beaver
(14.04LTS) (16.04LTS) (17.04) (17.10) (18.04LTS)
Released 2014-04-17 2016-04-21 2017-04-17 2017-10-19 2018-04
Supported to (2019-04) (2021-04) (2018-01) (2018-07) (2023-04)
GCC
g++-4.8 ports universe universe universe TODO
4.8.2-19ubuntu1 4.8.5-4ubuntu2 4.8.5-4ubuntu4 4.8.5-4ubuntu6 TODO
security xenial-updates zesty-updates TODO
4.8.4-2ubuntu1~14.04.3 N/A N/A TODO
trusty-updates xenial-backports zesty-backports TODO
4.8.4-2ubuntu1~14.04.3 N/A N/A TODO
trusty-backports
N/A
g++-4.9 main universe universe universe TODO
N/A 4.9.3-13ubuntu2 4.9.4-2ubuntu1 N/A TODO
trusty-updates xenial-updates zesty-updates TODO
N/A N/A N/A TODO
trusty-backports xenial-backports zesty-backports TODO
N/A N/A N/A TODO
g++-5 main ports universe universe TODO
N/A 5.3.1-14ubuntu2 5.4.1-8ubuntu1 5.5.0-1ubuntu1 TODO
trusty-updates security zesty-updates TODO
N/A 5.4.0-6ubuntu1~16.04.4 N/A TODO
trusty-backports xenial-updates zesty-backports TODO
N/A 5.4.0-6ubuntu1~16.04.5 N/A TODO
xenial-backports
N/A
g++-6 main main ports universe TODO
N/A N/A 6.3.0-8ubuntu1 6.4.0-8ubuntu1 TODO
trusty-updates xenial-updates main TODO
N/A N/A 6.3.0-12ubuntu2 TODO
trusty-backports xenial-backports zesty-updates TODO
N/A N/A N/A TODO
zesty-backports
N/A
g++-7 main main main main TODO
N/A N/A N/A 7.2.0-8ubuntu3 TODO
trusty-updates xenial-updates xenial-updates TODO
N/A N/A N/A TODO
trusty-backports xenial-backports xenial-backports TODO
N/A N/A N/A TODO
Clang
clang-3.5 ports universe N/A N/A TODO
1:3.5~svn201651-1ubuntu1 1:3.5.2-3ubuntu1 N/A N/A TODO
security xenial-updates zesty-updates TODO
1:3.5-4ubuntu2~trusty2 N/A N/A TODO
trusty-updates xenial-backports zesty-backports TODO
1:3.5-4ubuntu2~trusty2 N/A N/A TODO
trusty-backports
N/A
clang-3.6 N/A universe N/A N/A TODO
N/A 1:3.6.2-3ubuntu2 N/A N/A TODO
trusty-updates/universe xenial-updates zesty-updates TODO
1:3.6-2ubuntu1~trusty1 N/A N/A TODO
trusty-backports xenial-backports zesty-backports TODO
N/A N/A N/A TODO
clang-3.7 N/A universe universe N/A TODO
N/A 1:3.7.1-2ubuntu2 1:3.7.1-3ubuntu4 N/A TODO
trusty-updates xenial-updates zesty-updates TODO
N/A N/A N/A TODO
trusty-backports xenial-backports zesty-backports TODO
N/A N/A N/A TODO
clang-3.8 security universe universe universe TODO
1:3.8-2ubuntu3~trusty5 1:3.8-2ubuntu1 1:3.8.1-18ubuntu1 1:3.8.1-24ubuntu7 TODO
trusty-updates/universe xenial-updates/universe zesty-updates TODO
1:3.8-2ubuntu3~trusty5 1:3.8-2ubuntu4 N/A TODO
trusty-backports xenial-backports zesty-backports TODO
N/A N/A N/A TODO
clang-3.9 security security ports universe TODO
1:3.9.1-4ubuntu3~14.04.3 1:3.9.1-4ubuntu3~16.04.2 1:3.9.1-5ubuntu1 1:3.9.1-17ubuntu1 TODO
trusty-updates/universe xenial-updates/universe security TODO
1:3.9.1-4ubuntu3~14.04.3 1:3.9.1-4ubuntu3~16.04.2 1:3.9.1-5ubuntu1.1 TODO
trusty-backports xenial-backports zesty-updates TODO
N/A N/A 1:3.9.1-5ubuntu1.1 TODO
zesty-backports TODO
N/A TODO
clang-4.0 N/A security main universe TODO
N/A 1:4.0-1ubuntu1~16.04.2 1:4.0-1ubuntu1 1:4.0.1-6 TODO
trusty-updates xenial-updates zesty-updates TODO
N/A 1:4.0-1ubuntu1~16.04.2 N/A TODO
trusty-backports xenial-backports zesty-backports TODO
N/A N/A N/A TODO
clang-5.0 N/A N/A N/A universe TODO
N/A N/A N/A 1:5.0-3 TODO
trusty-updates xenial-updates zesty-updates TODO
N/A N/A N/A TODO
trusty-backports xenial-backports zesty-backports TODO
N/A N/A N/A TODO
libc++-dev
1.0 universe
1.0~svn199600-1
trusty-updates
N/A
trusty-backports
N/A
3.7 universe
3.7.0-1
xenial-updates/universe
3.7.0-1ubuntu0.1
xenial-backports
N/A
3.9 ports universe
3.7.0-1 3.9.1-3
universe
3.9.1-2
zesty-updates
N/A
zesty-backports
N/A
4.0 TODO
TODO
5.0 TODO
TODO
```
Table first compiled: 28 October 2017.
Last updated: 28 October 2017.
### <A name="compilers_in_fedora"/> Fedora
A short list of Fedora releases tells a similar story
to the Ubuntu distribution.
```text
25 26 27 28
Released 2016-11-22 2017-07-11 (2017-11-14) (2018-05-01)
Supported to TODO TODO TBD TBD
gcc-c++ 6.4.1-1.fc25 7.2.1-2.fc26 7.2.1-2.fc27 TODO
g++ 6.4.1 20170727 7.2.1 20170915 7.2.1 20170915 TODO
(Red Hat 6.4.1-1) (Red Hat 7.2.1-2) (Red Hat 7.2.1-2)
clang 3.9.1-2.fc25 4.0.1-5.fc26 4.0.1-5.fc27 TODO
clang++ 3.9.1 4.0.1 4.0.1 TODO
(tags/RELEASE_391/final (tags/RELEASE_401/final) (tags/RELEASE_401/final)
libcxx-devel 3.9.1-1.fc25 4.0.1-3.fc26 4.0.1-3.fc27 TODO
```
Table first compiled: 28 October 2017
Last updated: 9 November 2017
## <A name="tested_configurations"/> Tested configurations
Before release, Trompeloeil is tested with the following configurations
of compiler, language dialect, and standard library.
### GCC
Last updated: 3 June 2019
Key:
- `N/A`: The combination `g++-4.8/c++11/libc++` leads to
compile errors and is not currently supported. Further investigation
may change this outcome.
- `--`: The version of `libstdc++-v3` lacks a definition of the
`_GLIBCXX_RELEASE` macro.
- `stdc++` means `libstdc++-v3` from GCC.
- `c++` means `libc++` from Clang.
`g++-latest` means the "live at head" build of `g++`.
```text
Compiler Mode stdc++ c++
-std= __GLIBCXX__ _GLIBCXX_RELEASE _LIBCPP_VERSION
---------- ---- ------------------------------ ---------------
g++-4.8 c++11 20150623 -- N/A
g++-4.9 c++11 20160726 -- 8000
c++14
g++-5 c++11 20171010 -- 8000
c++14
c++17
g++-6 c++11 20181026 -- 8000
c++14
c++17
g++-7 c++11 20190326 7 8000
c++14
c++17
g++-8 c++11 20190406 8 8000
c++14
c++17
c++2a
g++-9 c++11 20190402 9 8000
c++14
c++17
c++2a
g++-latest c++11 20190421 9 8000
c++14
c++17
c++2a
```
### Clang
`clang++-latest` means the "live at head" version of `clang++`.
```text
Compiler Mode stdc++ c++
-std= __GLIBCXX__ _GLIBCXX_RELEASE _LIBCPP_VERSION
---------- ---- ------------------------------ ---------------
clang++-3.5 c++11 20190326 7 1101
c++14
clang++-3.6 c++11 20190326 7 1101
c++14
clang++-3.7 c++11 20190326 7 3700
c++14
clang++-3.8 c++11 20190326 7 3800
c++14
clang++-3.9 c++11 20190402 9 3900
c++14
clang++-4.0 c++11 20190402 9 4000
c++14
clang++-5.0 c++11 20190402 9 5000
c++14
c++17
c++2a
clang++-6.0 c++11 20190402 9 6000
c++14
c++17
c++2a
clang++-7 c++11 20190402 9 7000
c++14
c++17
c++2a
clang++-8 c++11 20190402 9 8000
c++14
c++17
c++2a
clang++-latest c++11 20190402 9 9000
c++14
c++17
c++2a
```
### Microsoft Visual Studio
Last update: 3 June 2019
Tested with Visual Studio Community 2019 16.1.1 .
```text
Platform Toolset Configuration Platform
------------------------- ------------- --------
Visual Studio 2015 (v140) Debug x64
Visual Studio 2017 (v141) Release x86
Visual Studio 2019 (v142)
```
## <A name="testing_on_artful"/> Testing Trompeloeil on Artful Aardvark (Ubuntu 17.10)
The release of Artful Aardvark (Ubuntu 17.10) contains a number of issues
requiring workarounds if you want to compile and test Trompeloeil with
community supported compiler versions e.g. any version of `clang++`,
any version `g++` less than 7, or community supported libraries e.g.
any version of `libc++`.
Canonical supported compilers and libraries -
just `g++-7` with `libstdc++-v3` - do not have the issues described below,
but this is rather a narrow list for testing Trompeloeil on its
supported compilers and libraries.
### <A name="defect_to_string"/> `std::to_string()` is not defined for some versions of `libstdc++-v3`
Affects: `libstdc++-v3` from these packages
- `libstdc++-4.8-dev:amd64 4.8.5-4ubuntu6`
- See: <https://bugs.launchpad.net/ubuntu/+source/gcc-4.8/+bug/1725847>
- `libstdc++-5-dev:amd64 5.5.0-1ubuntu1`
- See: <https://bugs.launchpad.net/ubuntu/+source/gcc-5/+bug/1725848>
Workaround: Add `-D_GLIBCXX_USE_C99=1` to your compiler command lines.
### <A name="defect_xlocale"/> Glibc 2.26 no longer supplies `xlocale.h`
The version of `glibc` in package `libc6-dev (2.26-0ubuntu2)`
drops support for `xlocale.h`.
`libc++` tracked this change and supplied a fix for 5.0.
See: "Fix libcxx build with glibc 2.26+ by removing xlocale.h include." \
Available: <https://github.com/llvm-mirror/libcxx/commit/6e02e89f65ca1ca1d6ce30fbc557563164dd327e> \
Accessed: 11 November 2017
But Artful Aardvark ships package `libc++-dev 3.9.1-3`.
As a consequence, no software using `libc++` out-of-the-box version
can compile on Artful.
Workaround: Create a symlink from `locale.h` to `xlocale.h`
```text
cd /usr/include
sudo ln -s locale.h xlocale.h
```
### <A name="defect_signbit"/> Glibc 2.26 `std::signbit()` broken for GCC compilers < 6
A defect in GLIBC 2.26 prevents programs using `signbit()` from `math.h`
from compiling with `g++-4.8`, `g++-4.9`, or `g++-5`.
This happens to include any uses of `libc++`, which requires a
functioning `signbit()` to compile function template `__libcpp_signbit()`
in file `math.h`.
The Clang compilers happen to work with this part of `glibc` 2.26
as they don't implement 128-bit floating point and a different
code path is followed, even for the earliest supported compilers.
See: <https://bugs.launchpad.net/ubuntu/+source/glibc/+bug/1725869>
Workaround: Patch your local copy of `math.h` in `glibc` with the
fix from `glibc` upstream, found by following the links in this bug report:
See: "Bug 22296 - glibc 2.26: signbit build issue with Gcc 5.5.0 on x86_64" \
Available: <https://sourceware.org/bugzilla/show_bug.cgi?id=22296> \
Accessed: 11 November 2017
### <A name="artful_conclusion"/> Conclusion
Hopefully updated packages for `glibc` (`libc6-dev`), `libc++`, and
`libstdc++-dev` for `g++-4.8` and `g++-5` will be released allowing
patch-free building and testing of Trompeloeil on Artful Aardvark.
A better strategy may be to build GLIBC, GCC 4.8, GCC 5.x, and `libc++`
from source and use these to build your software. Then consider
contributing your build to the Ubuntu Community; you just might be the
"support" in "community supported".
## <A name="incomplete_stdlib"/> Supporting incomplete standard libraries
Some platforms, especially MCUs with RTOS, only have partial support for the
standard library `<atomic>` and `<mutex>` headers used by trompeloeil.
In many cases, it is possible to provide shims or custom implementations
of the necessary parts.
### <A name="custom_recursive_mutex"/> Replacing `std::recursive_mutex`
To use your own recursive mutex, define `TROMPELOEIL_CUSTOM_RECURSIVE_MUTEX`
either before including the Trompeloeil header
(e.g. `#define TROMPELOEIL_CUSTOM_RECURSIVE_MUTEX`) or as preprocessor
definition (e.g. GCC: `-DTROMPELOEIL_CUSTOM_RECURSIVE_MUTEX`).
Now define in one translation unit your custom recursive mutex for trompeloeil.
```cpp
namespace trompeloeil {
std::unique_ptr<custom_recursive_mutex> create_custom_recursive_mutex() {
class custom : public custom_recursive_mutex {
void lock() override { mtx.lock(); }
void unlock() override { mtx.unlock(); }
private:
mylib::recursive_mutex mtx;
};
return std::make_unique<custom>();
}
}
```
### <A name="custom_std_atomic"/> Replacing `std::atomic<T>`
To use your own implementation of `std::atomic<T>`,
define `TROMPELOEIL_CUSTOM_ATOMIC` and make sure there is a header
`trompeloeil/custom_atomic.hpp` somewhere in the include search path.
This header should contain a class template `trompeloeil::atomic<T>`
that implements (part of) the interface of `std::atomic<T>`:
```cpp
namespace trompeloeil
{
template <typename T>
class atomic
{
public:
atomic() : m_atomic()
{
}
explicit atomic(const T initial) : m_atomic(initial)
{
}
T operator=(T desired)
{
m_atomic.store(desired);
return m_atomic.load();
}
operator T() const
{
return m_atomic.load();
}
private:
mylib::atomic<T> m_atomic;
};
}
```
### <A name="custom_std_unique_lock"/> Replacing `std::unique_lock<T>`
To use your own implementation of `std::unique_lock<T>`,
define `TROMPELOEIL_CUSTOM_UNIQUE_LOCK` and make sure there is a header
`trompeloeil/custom_unique_lock.hpp` somewhere in the include search path.
This header should contain a class template `trompeloeil::unique_lock<T>`
that implements (part of) the interface of `std::unique_lock<T>`:
```cpp
namespace trompeloeil
{
template <typename Mutex>
class unique_lock
{
public:
unique_lock() noexcept : m_mutex(nullptr)
{
}
explicit unique_lock(Mutex& mutex) : m_mutex(&mutex)
{
m_mutex->lock();
}
unique_lock(const unique_lock&) = delete;
unique_lock(unique_lock&& other) noexcept : m_mutex(nullptr)
{
std::swap(other.m_mutex, m_mutex);
}
unique_lock& operator=(const unique_lock&) = delete;
unique_lock& operator=(unique_lock&& other) noexcept
{
std::swap(other.m_mutex, m_mutex);
}
~unique_lock()
{
if (m_mutex)
{
m_mutex->unlock();
}
}
private:
Mutex* m_mutex;
};
}
```
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