https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102399
Bug ID: 102399
Summary: Cannot mix GCC and C++11 / C23 attribute syntax
Product: gcc
Version: 12.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: dangelog at gmail dot com
Target Milestone: ---
Hello,
If one tries to mix GCC's attribute syntax (__attribute__) and with C++11 / C23
([[attribute]]), GCC rejects the code (no matter what the order of the
attributes is):
#define EXPORT __attribute__((visibility("default")))
struct [[nodiscard]] EXPORT Foo { Foo(); };
https://gcc.godbolt.org/z/W868xjeMq
While a workaround exists (by sticking to the same "kind" of attribute syntax),
it's not always possible or easy to achieve in big codebases, where for
compatibility/legacy reasons the attributes are expanded via macros and can
expand to a random combination of GCC or C++ attributes.
For comparison, Clang and MSVC allow mixed syntaxes.
