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Merge pull request #273 from boostorg/no_unique_address

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Add BOOST_ATTRIBUTE_NO_UNIQUE_ADDRESS.
This commit is contained in:
jzmaddock
2019-04-03 18:09:33 +01:00
committed by GitHub
parent fb746fc6fb 6ef16c8d90
commit 9a79d0b155
3 changed files with 16 additions and 0 deletions
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2
doc/macro_reference.qbk
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@ -1277,6 +1277,8 @@ Usage example:
can be used to disable compiler warnings relating to unused types or variables.]] can be used to disable compiler warnings relating to unused types or variables.]]
[[`BOOST_ATTRIBUTE_NODISCARD`][Expands to `[[nodiscard]]` when this is available - [[`BOOST_ATTRIBUTE_NODISCARD`][Expands to `[[nodiscard]]` when this is available -
can be used to create a warning when a type or variable is unused.]] can be used to create a warning when a type or variable is unused.]]
[[`BOOST_ATTRIBUTE_NO_UNIQUE_ADDRESS`][Expands to `[[no_unique_address]]` when this is available -
can be used to indicate that a non-static data member need not have a unique address (for example empty classes).]]
[[`BOOST_MAY_ALIAS`, `BOOST_NO_MAY_ALIAS`][ [[`BOOST_MAY_ALIAS`, `BOOST_NO_MAY_ALIAS`][
`BOOST_MAY_ALIAS` expands to a type attribute that can be used to mark types that may `BOOST_MAY_ALIAS` expands to a type attribute that can be used to mark types that may
alias other types. Pointers or references to such marked types can be used to access objects alias other types. Pointers or references to such marked types can be used to access objects

6
include/boost/config/detail/suffix.hpp
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@ -999,10 +999,16 @@ namespace std{ using ::type_info; }
#if __has_cpp_attribute(nodiscard) #if __has_cpp_attribute(nodiscard)
# define BOOST_ATTRIBUTE_NODISCARD [[nodiscard]] # define BOOST_ATTRIBUTE_NODISCARD [[nodiscard]]
#endif #endif
#if __has_cpp_attribute(no_unique_address)
# define BOOST_ATTRIBUTE_NO_UNIQUE_ADDRESS [[no_unique_address]]
#endif
#endif #endif
#ifndef BOOST_ATTRIBUTE_NODISCARD #ifndef BOOST_ATTRIBUTE_NODISCARD
# define BOOST_ATTRIBUTE_NODISCARD # define BOOST_ATTRIBUTE_NODISCARD
#endif #endif
#ifndef BOOST_ATTRIBUTE_NO_UNIQUE_ADDRESS
# define BOOST_ATTRIBUTE_NO_UNIQUE_ADDRESS
#endif
#define BOOST_STATIC_CONSTEXPR static BOOST_CONSTEXPR_OR_CONST #define BOOST_STATIC_CONSTEXPR static BOOST_CONSTEXPR_OR_CONST

8
test/helper_macro_test.cpp
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@ -42,6 +42,13 @@ struct BOOST_ATTRIBUTE_NODISCARD nodiscard_struct {};
#define test_fallthrough(x) foobar(x) #define test_fallthrough(x) foobar(x)
struct empty {};
struct no_unique
{
int a;
BOOST_ATTRIBUTE_NO_UNIQUE_ADDRESS empty b;
};
int main() int main()
{ {
@ -56,6 +63,7 @@ int main()
if(BOOST_UNLIKELY(!result)) if(BOOST_UNLIKELY(!result))
always_throw(); always_throw();
nodiscard_struct s; nodiscard_struct s;
no_unique no_un;
} }
catch(int) catch(int)
{ {