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Diffstat (limited to 'boost/outcome/experimental/status-code/error.hpp')
-rw-r--r-- | boost/outcome/experimental/status-code/error.hpp | 65 |
1 files changed, 65 insertions, 0 deletions
diff --git a/boost/outcome/experimental/status-code/error.hpp b/boost/outcome/experimental/status-code/error.hpp new file mode 100644 index 0000000000..b84ff78d19 --- /dev/null +++ b/boost/outcome/experimental/status-code/error.hpp @@ -0,0 +1,65 @@ +/* Proposed SG14 status_code +(C) 2018-2019 Niall Douglas <http://www.nedproductions.biz/> (5 commits) +File Created: Feb 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_SYSTEM_ERROR2_ERROR_HPP +#define BOOST_OUTCOME_SYSTEM_ERROR2_ERROR_HPP + +#include "errored_status_code.hpp" +#include "system_code.hpp" + +BOOST_OUTCOME_SYSTEM_ERROR2_NAMESPACE_BEGIN + +/*! An erased `system_code` which is always a failure. The closest equivalent to +`std::error_code`, except it cannot be null and cannot be modified. + +This refines `system_code` into an `error` object meeting the requirements of +[P0709 Zero-overhead deterministic exceptions](https://wg21.link/P0709). + +Differences from `system_code`: + +- Always a failure (this is checked at construction, and if not the case, +the program is terminated as this is a logic error) +- No default construction. +- No empty state possible. +- Is immutable. + +As with `system_code`, it remains guaranteed to be two CPU registers in size, +and move relocating. +*/ +using error = errored_status_code<erased<system_code::value_type>>; + +#ifndef NDEBUG +static_assert(sizeof(error) == 2 * sizeof(void *), "error is not exactly two pointers in size!"); +static_assert(traits::is_move_relocating<error>::value, "error is not move relocating!"); +#endif + +BOOST_OUTCOME_SYSTEM_ERROR2_NAMESPACE_END + +#endif |