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Diffstat (limited to 'boost/outcome/policy/fail_to_compile_observers.hpp')
-rw-r--r-- | boost/outcome/policy/fail_to_compile_observers.hpp | 60 |
1 files changed, 60 insertions, 0 deletions
diff --git a/boost/outcome/policy/fail_to_compile_observers.hpp b/boost/outcome/policy/fail_to_compile_observers.hpp new file mode 100644 index 0000000000..ac41ac13c5 --- /dev/null +++ b/boost/outcome/policy/fail_to_compile_observers.hpp @@ -0,0 +1,60 @@ +/* Policies for result and outcome +(C) 2018-2019 Niall Douglas <http://www.nedproductions.biz/> (59 commits) +File Created: Sep 2018 + + +Boost Software License - Version 1.0 - August 17th, 2003 + +Permission is hereby granted, free of charge, to any person or organization +obtaining a copy of the software and accompanying documentation covered by +this license (the "Software") to use, reproduce, display, distribute, +execute, and transmit the Software, and to prepare derivative works of the +Software, and to permit third-parties to whom the Software is furnished to +do so, all subject to the following: + +The copyright notices in the Software and this entire statement, including +the above license grant, this restriction and the following disclaimer, +must be included in all copies of the Software, in whole or in part, and +all derivative works of the Software, unless such copies or derivative +works are solely in the form of machine-executable object code generated by +a source language processor. + +THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR +IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, +FITNESS FOR A PARTICULAR PURPOSE, TITLE AND NON-INFRINGEMENT. IN NO EVENT +SHALL THE COPYRIGHT HOLDERS OR ANYONE DISTRIBUTING THE SOFTWARE BE LIABLE +FOR ANY DAMAGES OR OTHER LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE, +ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER +DEALINGS IN THE SOFTWARE. +*/ + +#ifndef BOOST_OUTCOME_POLICY_FAIL_TO_COMPILE_OBSERVERS_HPP +#define BOOST_OUTCOME_POLICY_FAIL_TO_COMPILE_OBSERVERS_HPP + +#include "base.hpp" + +BOOST_OUTCOME_V2_NAMESPACE_EXPORT_BEGIN + +#define BOOST_OUTCOME_FAIL_TO_COMPILE_OBSERVERS_MESSAGE \ + "Attempt to wide observe value, error or " \ + "exception for a basic_result/basic_outcome given an EC or EP type which is not void, and for whom " \ + "trait::is_error_code_available<EC>, trait::is_exception_ptr_available<EC>, and trait::is_exception_ptr_available<EP> " \ + "are all false. Please specify a NoValuePolicy to tell basic_result/basic_outcome what to do, or else use " \ + "a more specific convenience type alias such as unchecked<T, E> to indicate you want the wide " \ + "observers to be narrow, or checked<T, E> to indicate you always want an exception throw etc." + +namespace policy +{ + struct fail_to_compile_observers : base + { + template <class Impl> static constexpr void wide_value_check(Impl && /* unused */) { static_assert(!std::is_same<Impl, Impl>::value, BOOST_OUTCOME_FAIL_TO_COMPILE_OBSERVERS_MESSAGE); } + template <class Impl> static constexpr void wide_error_check(Impl && /* unused */) { static_assert(!std::is_same<Impl, Impl>::value, BOOST_OUTCOME_FAIL_TO_COMPILE_OBSERVERS_MESSAGE); } + template <class Impl> static constexpr void wide_exception_check(Impl && /* unused */) { static_assert(!std::is_same<Impl, Impl>::value, BOOST_OUTCOME_FAIL_TO_COMPILE_OBSERVERS_MESSAGE); } + }; +} // namespace policy + +#undef BOOST_OUTCOME_FAIL_TO_COMPILE_OBSERVERS_MESSAGE + +BOOST_OUTCOME_V2_NAMESPACE_END + +#endif |