https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88806
Bug ID: 88806
Summary: extern "C" variables declared in different namespaces
are considered different
Product: gcc
Version: 8.2.1
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: m101010a at gmail dot com
Target Milestone: ---
$ cat x.cpp
namespace A { extern "C" int g; }
namespace B { extern "C" int g; }
using namespace A;
using namespace B;
void f() { g; }
$ g++ -fsyntax-only x.cpp
x.cpp: In function ‘void f()’:
x.cpp:5:12: error: reference to ‘g’ is ambiguous
void f() { g; }
^
x.cpp:2:30: note: candidates are: ‘int B::g’
namespace B { extern "C" int g; }
^
x.cpp:1:30: note: ‘int A::g’
namespace A { extern "C" int g; }
^
$ g++ -v
Using built-in specs.
COLLECT_GCC=g++
COLLECT_LTO_WRAPPER=/usr/lib/gcc/x86_64-pc-linux-gnu/8.2.1/lto-wrapper
Target: x86_64-pc-linux-gnu
Configured with: /build/gcc/src/gcc/configure --prefix=/usr --libdir=/usr/lib
--libexecdir=/usr/lib --mandir=/usr/share/man --infodir=/usr/share/info
--with-bugurl=https://bugs.archlinux.org/
--enable-languages=c,c++,ada,fortran,go,lto,objc,obj-c++ --enable-shared
--enable-threads=posix --enable-libmpx --with-system-zlib --with-isl
--enable-__cxa_atexit --disable-libunwind-exceptions --enable-clocale=gnu
--disable-libstdcxx-pch --disable-libssp --enable-gnu-unique-object
--enable-linker-build-id --enable-lto --enable-plugin
--enable-install-libiberty --with-linker-hash-style=gnu
--enable-gnu-indirect-function --enable-multilib --disable-werror
--enable-checking=release --enable-default-pie --enable-default-ssp
--enable-cet=auto
Thread model: posix
gcc version 8.2.1 20181127 (GCC)
This is part of the example from the C++ standard section 9.7.3
(namespace.udir) paragraph 6, with g changed from a function to a variable.
Since A::g and B::g refer to the same entity, there should be no ambiguity
between them.
